OPA2228 is very nice, has pleasant bass, lots of air and richness in mids, and silky highs. If you like AD8066, you will enjoy OPA2228. It lacks a bit of detail and soundstage deepness. OPA2227 in spite of being a compensated brother of OPA2228 sounds totally different - slow, laid back, dull, awfully boring. The only positive thing is his bass. Overall, one of the worst op-amps ever used in audio IMHO. When I was playing with Cmoy-like designs, OPA2228 was one of my favourites, but I also enjoyed TLE2082 and AD8620. AD8066 alone is for me too mellow and laid back, but sweet, with good space. I went to higher power and more complicated designs so I discontinued using even AD8397, but this one is a real amplifier, not just sound modifier.
OPA2227 and 2228 is totally different in term of its sound signature.
I basically agree what majkel said with slightly different idea.
2227 is like bass heavy version of 2134. Better bass, slightly better mids.
That could make you feel the bass dominates other part of sound, make it boring or imbalnced. I prefer 2227 over 2134 for it is better at bass department, but neither of them will be my main OP. Just not with my liking.
I generally like laid back characteristic of BB OPs, but not with those OPs. I'd use JRC4580 that everyone think low about rather than 2227. Even if I loose BB characteristics by doing that, I know at least I can get very flat response, which is not exciting but not mucky at all.
2228 is little different story. Its quite different from 2227 even if they share similiar design. It sound clear, and airy. bass is not strong like that of 2227, but lower and deep. That makes the sound feel wide and 3D-ish. Mids feels like little recessed due to its clear highs and deep lows. Female vocal is great with this OP, but male vocal is like... something is missing. Its very good at delicate sound, but not for muscular sound. To me, the sound of 2228 feels like the sound when you adjust your equalizer V shape. Some people find this fantastic, others may find this artificial.