I'd say he's a little above average from what I've seen.  For example
http://www.chaosorc.com has the galleon at $25-30 US, whereas Big Lemon is around $50-60 US.  But I'd say it's case by case basis for sure.
I nabbed a complete unpunched copy of Man O'War from ebay for $70 US.  Plague Fleet and Seas of Blood seem to hit the $120-150 mark.  I'm also bidding on another copy of the main set, with Seas of Blood an a couple fleets.
We took a look through the boxes at the LGS that someone brought in and found about 8 more boxes of ships.  So in total here's what we have nabbed so far, all of which was NiB, still shrinkwrapped:
Chaos Dwarf Battle Fleet (Thunderfire, 3 Hull Destroyers, Great Taurus)
Dark Elf Death Fortresses (3)
Dark Elf Manticore Riders (3)
Khorne Bloodship (1)
Slaanesh Hellship (1)
Tzeentch Great Winged Terror (1)
Tzeentch Bane Tower (1)
Nurgle Plagueship (1)
Nurgle Plaguecrushers (3)
Skaven Warp-Raiders (3)
Skaven Deathburners (3)
Dwarf Gyrocopters (3)
Dwarf Nautilus (3)
2 other Dwarf boxes (I can't recall which)
Norse Longships (3)
Imperial Griffon Riders (3)
Imperial Warglleys (3)
Imperial Wolfship Squadron (3)
High Elf Dragon Riders (3)
High Elf Hawkships (3)
Monsters of the Deep 1 (4)
Monsters of the Deep 2 (4)
So we've managed to nail down a good chunk, but there are definately some things we're still looking for.  So if anyone has any of the following up for grabs, please let me know.  And I'll send Erik a PM ASAP.
Dark Elf Black Ark
Dark Elf Doomreavers
Skaven Doombringer (currently bidding for on eBay)Chaos Dwarf Great Leveller Battlebarge
Chaos Dwarf Thunder-Rollers
Khorne Ironsharks
Slaanesh Hellrammers
Slaanesh Hellslicers
Tzeentch Lord of Change
Chaos Deathgalleys (unless these are just the plastics from the main box)
Norse Kingship
Imperial Greatship
Bretonnian Galleon
Bretonnian Buccaneer
Bretonnian Corsair
High Elf Dragonship
High Elf Eagleship
Orc Bigchukka
Orc Drilla Killa
Orc Hulk
We'll probably get around to nabbing Uncharted Seas in the new year, but my buddy and I really want to nail down some Man O'War, because it's one of those nostalgic things.