wongsan: eh.. well.. the colours do look slightly different between #1 and #2. but then again, you had shifted slightly, and also the light may have changed. so this real world test might not be a good indicator... that being said, without #1 to compare... i would be pretty ok with #2.
i personally also shot a roll with a uvir filter on a 50mm (on the way by the way thing, just to test out an M3 i got recently... thanks eamesboy!), looks ok to me.
will try out a few with a 21mm and uvir if i have the time.