Had a game this evening against IJW Wartrader's Death Guard. It was a 2-0 victory to Ian at the end of turn 3, but was a much closer business than that result would indicate.
Main take away from both players: the list feels as though nothing is particularly under or overcosted. There's differences even in the core Tau units (Fire Warriors, XV8) that makes the list feel significantly different from vanilla Tau, whilst still feeling very Tau. I didn't take enough markerlights, but that's a me problem

Lists as below
Vior'La Tau
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FIRE WARRIOR BREACHER CADRE [350] Shas'O, 3x Fire Warriors, 2x Pathfinders, 3x Devilfish
PATHFINDERS [225] 6x Pathfinders, 2x Gun Drones
VIOR'LA XV8 CRISIS SUITS [400] Shas'El, 8x XV8
HEAVY BATTLESUITS [350] Shas'El, 3x Riptide
KV128 STORMSURGES [250] 2x Stormsurge
KV139 SUPREMACY [225] Heavy Rail Cannon
KV139 SUPREMACY [225] Pulse Ordnance Multi Driver
XV88 BROADSIDES [300] 6x Broadside
STEALTH GROUP [300] 3x XV15, 3x XV95 (this was an accident which brought me over points slightly, meant to only be 2x XV95)
RAZORSHARK SQUADRON [200] 3x Razorshark
SUNSHARK SQUADRON [200] 2x Sunshark
Death Guard (Epic UK v210617)
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DEATH GUARD RETINUE [650] Chaos Lord, Plague Tower, 4 Plague Marines, 3 Havocs
DEATH GUARD RETINUE [625] Chaos Lord, 7 Plague Marines, Plague Tower
DEATH GUARD DEFILER PACK [275] 4 Defilers
DEATH GUARD DEFILER PACK [275] 4 Defilers
PLAGUE ZOMBIE INFESTATION [175] 3+2D6 Plague Zombies
PLAGUE ZOMBIE INFESTATION [175] 3+2D6 Plague Zombies
PLAGUEHOUND TITAN [275]
PLAGUEHOUND TITAN [275]
PLAGUEHOUND TITAN [275]
I didn't get a play by play noted down, so I'll run through each formation and give a summary of what I thought.
Breachers: Didn't do all that much, by design. Stayed at the back and acted as a mobile reserve. It's nice having the Shas'O somewhere else than a Crisis Cadre. Pathfinder upgrade is a useful variation. The uniformity of dice in the Breacher stands themselves did somewhat ease the normal admin load of getting in 15cm with vanilla Fire Warriors and many different types of dice being rolled

Pathfinders: I like the option of foot Pathfinders. Felt fine, but probably needs more of a stress test to see what taking loads of them as cheap, scouting core formations with markerlights does!
XV8: A nice variation on standard XV8s. In some ways having minimum range of 30cm helps narrow the mind towards the main objective of XV8s- getting into very close range and destroying stuff. Melted a Plague Tower in turn 2 after winning the initiative, then got (Plague)hounded out of existence to give Ian BTS. High risk, high reward. Not having to worry about the Shas'O in there was nice, but I think a Shas'O option in keeping with the fluff wouldn't hurt.
Riptides: How are these guys not a done deal yet? They move fast, shoot fast and tank being shot at but melt in engagements due to lack of Fearless. This is fine. Didn't get to test the AA guns admittedly as Ian never takes aircraft, but I think it's a useful addition in exchange for weaker non-MW shots.
Stormsurges: Again, the basic formula for these guys is well established. Due to poor play on my part didn't get to use the Destroyer Missiles, but I think both 2x Destroyer Missiles or 4x one-shot Destroyer Missiles (the old pattern) are fine.
Supremacy (Heavy Rail Cannon): Vior'La already had very ready access to Macro, so a Volcano Cannon equivalent seems a little excessive. This game however it flubbed two rounds of shooting against a Plague Tower, doing a grand total of one point of damage.

Compared to a Shadowsword say, it feels fine, just unecessary is all. If you actually want people to take Stormsurges then I'd remove this option.
Supremacy (Pulse Ordnance Multi Driver): After having a Minigeddon game using the new POMD I was really worried about it. 3BP template Indirect when I played with it before was never really an issue. 4x Disrupt shots benefitting from Markerlights AND Sustain Firing seemed way better. It didn't do that much this game though, and it is an interesting difference from normal artillery. Further testing required.
Broadsides: They're Broadsides. They don't get much love but are actually tough as nails. Next

(Although there is a typo in that they've got 90cm Railguns on the quick ref sheet!)
Stealth Group: Ghostkeels add an interestign variation. Got no use out of them as I teleported them turn two and they immediately got pounced on and broken for the rest of the game. Further testing required as a result
Razorsharks: Interesting alternative to Barracuda. I always find Hellblades pretty gnarly and these seem similar. However the Razorsharks feel like they need a little bit more shooty.
Sunsharks: They 'aight I guess. Maybe give the BP a special rule for a bit of pizzaz, but they're fine.
So aside from minor quibbles about some choices the list feels in the right place generally. Hope this helped, hopefully I can playtest next week too
