The fast version of v3 speeds up many of the games I tested which were slightly too slow to have an enjoyable game with... here's the (quick) results.
Playable
Wario Ware - Sound bad, but very playable at FS2 in v3fast!
Kuru Kuru Kururin (E) - Now playable in v3fast. Not sure how fast its supposed to be in comparison to the real game, but it plays well. Occasional slowdown, but pretty good!
Chu Chu Rocket (U) - works nicely, even better in v3fast
PacMan Collection - still playable
Mr Driller 2 (E) - menus perfect, game works, but slightly too slowly. Not much difference between v2 and v3 fast.
Rampage Puzzle Attack (U) - Distorted sound, a little slow, but now very playable
Spyro Season of Ice (U) - Works, but still very noisy! (picture is flickery in v3fast)
Super Bust a Move (m5) - almost perfect, only slightly choppy sound now, on occasion
Super Mario Advance (U) - works quite well at FS0, even better at FS1 or FS2
Not so great
Gradius Advance (E) (!) - goes into game, faster than v2, but still too slow
Tony Hawks Pro Skater 2 (U) - slow, but works
Max Payne (U) - still slow, but works
Namco Museum (J)(Cezar) - works very well in v3fast, sound still choppy
Won't Run
Colin McRae Rally 2 (U) - intro much faster, can get through select screen then 'whites out'
Need For Speed Underground (UE) (M4) - Hangs at EA logo
I'm very impressed so far...
EDIT: As suggested below, I added the version codes from the GoodRoms list. If only I'd kept the GoodRom number with each ROM when I transferred them.
For the future, I think a compatibility list could be created by listing the games from 0001-2600, rather than by game and (U/J) etc...
Playable
Wario Ware - Sound bad, but very playable at FS2 in v3fast!
Kuru Kuru Kururin (E) - Now playable in v3fast. Not sure how fast its supposed to be in comparison to the real game, but it plays well. Occasional slowdown, but pretty good!
Chu Chu Rocket (U) - works nicely, even better in v3fast
PacMan Collection - still playable
Mr Driller 2 (E) - menus perfect, game works, but slightly too slowly. Not much difference between v2 and v3 fast.
Rampage Puzzle Attack (U) - Distorted sound, a little slow, but now very playable
Spyro Season of Ice (U) - Works, but still very noisy! (picture is flickery in v3fast)
Super Bust a Move (m5) - almost perfect, only slightly choppy sound now, on occasion
Super Mario Advance (U) - works quite well at FS0, even better at FS1 or FS2
Not so great
Gradius Advance (E) (!) - goes into game, faster than v2, but still too slow
Tony Hawks Pro Skater 2 (U) - slow, but works
Max Payne (U) - still slow, but works
Namco Museum (J)(Cezar) - works very well in v3fast, sound still choppy
Won't Run
Colin McRae Rally 2 (U) - intro much faster, can get through select screen then 'whites out'
Need For Speed Underground (UE) (M4) - Hangs at EA logo
I'm very impressed so far...
EDIT: As suggested below, I added the version codes from the GoodRoms list. If only I'd kept the GoodRom number with each ROM when I transferred them.
For the future, I think a compatibility list could be created by listing the games from 0001-2600, rather than by game and (U/J) etc...