The 505 I'm almost positive will read Adobe Digital editions (I have several PDFs on mine). It doesn't read as well as Sony's LRF format (it has problems recalibrating with pictures), but it is readable.
They potentially will come out with a wireless version, but not for a while. Personally I don't want a wireless version, and I like that Sony doesn't have it. As for color e-ink, I think we have a few years to wait before those come out in the market.
As for interface, a lot of people complain about Sony's software (it doesn't bother me), but luckily there is a program everyone loves called Calibre. You can find out about it on MobileRead. It also works with Macs, if you were so inclined. People use Calibre as a replacement for Sony's software.
I love my Sony, I find it easy to use, ergonomic, and plain old pretty
I hope this helps answer your questions.