I've just come off playing 22(!) games in a row with this list in the last couple of months as a part of a builder league at my gaming club (about a 54% winrate, suggesting its pretty balanced.) Thanks to kyussinchains and frogbear for putting this together and to everyone who helped test it to get approved. I think it's in a pretty good place! Overall they are nicely slanted towards playing defensively with lots of tough, garrison-able units. Thunderfires are very good with 60cm range, their overwatch is punishing not to mention sustained fire. I've played against the following:
Black Legion
Dark Eldar
Krieg
Red Corsairs
IF mirror
Tyranids (both the standard EA and the Ragnarok drop list)
Yme-Loc Eldar from EpicUK
Squats
Iron Warriors
I find the defensive playstyle personally boring so it's been a challenge for me, but I've had some success playing a more siegebreaker version of the list but only against certain armies or players that garrisoned their own units and had some artillery I couldn't just turtle up against. Ultimately you lose a lot trying to be the aggressor without Thunderhawks or Drop Pods/Strike Cruisers and though I don't think trenches are particularly good, being able to start 3 units on Overwatch is clutch.
Mostly I've been playing something like this:
PREDATORS [250]
4 Annihilator
VINDICATOR [225]
4 Vindicator
FELLBLADE [325]
1 Fellblade
LAND SPEEDERS [200]
5 Land speeder
TERMINATORS [375]
4 Terminator units, Chaplain
THUNDERFIRE BATTERY [250]
4 Thunderfire Cannons
CENTURION [300]
2 Assault Centurion, 2 Devastator Centurion
CENTURION [300]
2 Assault Centurion, 2 Devastator Centurion
SCOUTS [175]
4 Scout units, Rhino, Razorback LAS
TACTICAL [375]
6 Tactical units, Supreme Commander, Rhino
TARANTULA SENTRY GUNS [100]
4 Tarantulas, 4 Emplacements
HYPERIOS PLATFORMS [125]
3 Hyperios Platforms
Happy to answer any questions anyone might have about how various units have performed. We have another guy in the league with the same score as me so far who's also playing IF but who likes the trenches:
VINDICATOR [300]
6 Vindicator
FELLBLADE [325]
1 Fellblade
THUNDERFIRE BATTERY [250]
4 Thunderfire Cannons
TACTICAL [550]
6 Tactical units, Supreme Commander, Hunter, 2 Dreadnought
DEVASTATOR [425]
4 Devastator units, 2 Bunkers + Trenches, 2 Dreadnought, Hunter
LAND SPEEDERS [200]
5 Land speeder
LAND SPEEDERS [200]
5 Land speeder
TERMINATORS [375]
4 Terminator units, Chaplain
TERMINATORS [375]
4 Terminator units, Captain
I've also tested the Thunderhawk Bomber, Storm Talons (both situationally good but probably not for use in a take all comers list) and all the Land Raider variants as well as Devastators and different combinations of Centurions. I think the Vindicators are probably a cut, even with 6 of them they just don't put out enough shots or move quickly enough to be very good which I feel is the same issue normal marine Vindis have. I think they could really benefit from a one-shot hunter-killer missile or something to beef up their firepower one time but I don't know if this is the place to test profiles like that.
I went back into the forums and read up all the threads I could find discussing the army; it's interesting to see the decisions made in development. If I had one suggestion, I find it weird that Assault Centurions have Meltaguns with the same shooting profile as Multi-Meltas, and that neither those nor the Heavy Flamers are represented by special rules in their FF. I'd echo Dave's suggestion, those two weapons could change to:
Meltaguns 15cm MW6+ (I think this is the only NetEA instance of these; they should be worse than Multi-Meltas)
AND (15cm) Small Arms, EA(+1), MW
Twin Heavy Flamer 15cm AP3+, IC
AND (15cm) Small Arms, EA(+1), IC
with the Assault Centurion profile going to 5+ FF. That way they get 3 dice per base but an average of 1 hit, same as before with two shots FF 4+, except they have a chance of inflicting an additional two hits and all weapon profiles are represented. That makes them feel more exciting along the lines of the Devastator Centurions which get four shots per base in shooting. Overall they are really constrained by not being able to take a character which helps balance them as a unit against Terminators. They have a totally different role and are a lot closer to an alternative to Tacticals/Devastators in Bunkers than they are to Terminators; their shooting is limited by any movement they do since they don't have meaningful IC further than 15cm, so they are best suited to being on overwatch on an objective and being tough to shift. The Devastators terrible CC means you want some Assaults as a screen and to deter charges so the mix works well. With Land Raiders they are too expensive (not rules wise but practically I think) and a 25cm assault vehicle is just ok - I'd rather Tacticals in Rhinos with a Chaplain.
I have some more out-there ideas too considering the list has one result in EpicUK tournaments so far and I haven't heard much interest in it since its approval. For one, Dreadnoughts are really difficult to want to take as upgrades to other formations because they are snipable as AVs. Maybe if it were possible to take Gun Emplacements with your Trench/Bunker setups they would be more appealing as you could put your Hunter, Dread etc. there for -1 to hit, and maybe could grant Dreadnoughts First Strike - that might be enough for me consider taking them. Gun Emplacements as an option for other tanks would also be interesting, they could work the same way (Vindicators getting FS FF4+ would be cool) and some tables have little terrain that grants -1 to hit for vehicles where they can still shoot. I would also love to see a 3-model Siege Dreadnought Talon from IA10; they'd be great garrisoned and able to charge onto an enemy objective. With this and Assault Marines without jump packs I think it would be possible to play an aggressive version of the list without too much warping.
I personally don't rate Devastators at all; I suppose it's nice to have a size 4 formation so you can garrison two Rapiers with them in bunkers, but trading two bases vs. Tacticals for one more AP5+/AT6+ shot and FF3+ is not worth it imo. I would like to see something modifying these to make them more appealing in IF since they seem like an iconic unit, but they face the same issue as standard Codex Devastators so I'm leery of proposing anything. I still find it odd that Long Fangs get 3x AP5/AT5 per base as though being old gives them more bullets. Even just two shots at AP4/AT5 to represent Heavy Bolters, Plasma Cannons and Lascannons along with MLs would be reasonable, or even 3xAP5/AT6 missile launchers per base - that's only four AT hits on a sustain or six against infantry outside cover.
Whirlwinds in Codex Marines seem quite bad and underplayed as far as I can tell; they are good in this list in some cases and I would love to see them be popular. That Castellan Ignore Cover upgrade sounds interesting. As it stands, adding two to get a second blast marker on the target unit is just not worth it I don't think, which is too bad for an upgrade that's unique.
The Techmarine is so cool but provides so little utility; you're basically paying 25pts for Leader on a formation that doesn't need to clear BMs to charge. I don't hate it but I wish it did a little more; maybe it gives one armour save re-roll for the unit per round, though that's finicky. If it's not going to be changed I think I would just make it an upgrade to the Bastion and take it off Thunderfires since it really doesn't do much there (though I do have one modelled!)
Another possible unique unit could be 3 Hunters, and/or the option to take Stalkers. 3 Hunters have solid AT at 60cm which is a big deal and would help with the AT weakness of the list along with being terrifying AA - maybe too good at 4x4+.
One of the core problems with the list is that AT weakness and I was thinking maybe a different marine Superheavy Tank could help with that, maybe 0-1 Falchion or Astraeus. You wouldn't be able to spam it and you'd have to carefully win the activation game to coax an enemy SHT out to shoot it, but it would give the list game against titans and Krieg where the foe can take ~11 4+ RA WEs at 3000 pts and you don't have the weight of marine combat activations to beat them in firefight/assault. The Fellblade is good but 2xMW3+ isn't enough there; you need to be in range to use the Lascannons to get its points cost worth and it dies to the kinds of units it would be good at countering (Shadowswords with 90cm range).
Other options for AT support could be the Thunderhawk CAS, that gives you some mobile AT that would also give you a way to attack enemy artillery that isn't an LV. You could also add rockets/krak missiles to the Storm Talon in lieu of the Heavy Bolters, the "Skyhammer missile launcher" has an AA attack as well so it'd still be comparable as a fighter. It kind of bothers me that the Storm Talons are Fighters with so much AA as they really look like ground attack units in comparison to the Stormhawk, which is more of an Interceptor, but I blame GW.
Anyway that's a big wall of text but 22 games later it's an interesting list and a unique intro to playing marines. I think given my playstyle I'm going to switch to Codex and run drop pods but I'm glad I gave the list such a shot. It is pretty tempting to go to Britcon or something and try to get a positive record in the EpicUK standings with them, maybe even give the Warlord a test. I may do a batrep for that this winter.