I don't have experience with the Airport express but I do know it's capabilities. As I understand the SB3 features beat the AE hands down for eg: you could use the SB3 remote to select your music library whereas AE you could not & the SB3 firmware is upgradeable.
One caveat about using the SB3 is the setup can be a bit technical & if you are not tech savvy like me, it might cause some frustration. The other caveat is Slimserver software to be used with SB3 is in constant development & can be buggy.
Aside from the caveats, the SB3 is an amazing product with a sound quality that will satisfy most audiophiles if properly setup.
Good luck...
One caveat about using the SB3 is the setup can be a bit technical & if you are not tech savvy like me, it might cause some frustration. The other caveat is Slimserver software to be used with SB3 is in constant development & can be buggy.
Aside from the caveats, the SB3 is an amazing product with a sound quality that will satisfy most audiophiles if properly setup.
Good luck...