The real difference between the two is the Fast Focus Live View on the A330. I have the older A350 (after switching from an XTi) and wouldn't be without FFLV. I did not notice the difference in the viewfinder size when I switched. I would say the greens, flash, low light focus, etc. differences would be insignificant.

I almost always use manual focus for macros, but seldom use the digital zoom for it. That may be just me and that I don't find it's use very convenient. I picked up a used Minolta AF macro lens for $350 and it is wondeful. Here are a couple of DBs that show the Minolta and Sony lenses that will work on a Sony body.

http://www.mhohner.de/sony-minolta/lenses.php

http://www.dyxum.com/lenses/index.asp

Any questions, just ask.

TF