I just downloaded the Macintosh version of the new software and installed it. The installer warned that installation would require a restart. When the install was done, Firefox came up, brought up this page
http://ebookstore.sony.com/howitworks/ , and cancelled the restart. {sigh} I restarted anyway, just to be sure.
The Mac version looks much like the old PC version. I was able to do a "File->Import files..." to consume all of the previous books I'd purchased from the Sony store. That worked fine. I confess some small sense of relief that my investment in Sony books was no longer relegated to the VirtualPC world. (There's one less reason to start Windows on my MacBook Pro!)
I then connected the PRS-505. That also worked first time. So far, so good.
Purchasing a book was next. I selected "The Guns of August" (not available in the Kindle store, by the way), added it to my cart, and proceeded to checkout. Along the way I needed to add my credit card information. When I thought I had completed the transaction, the Sony client brought up an error screen with an obscure HTTP error and told me to contact customer service. Yikes. I backed out and tried to buy the book again. This time the store told me I had already purchased it. OK. That's good. It won't let me buy it twice.
I was then able to navigate to the eBook store --> my account --> My eBooks/books I own page and download the new book. It worked, but I should point out this is still a far cry from the smooth interface that Amazon provides. It doesn't pass the muster of "would my mother call me for technical support if this happened to her?" The answer is most certainly "yes".
Sony is back in play for me because (a) they came out with a Macintosh client (and, yes, I am a dedicated and happy Calibre user), (b) they have made an effort to harmonize their pricing model closer to that of other eBook retailers, especially Amazon, and (c) their continued efforts like EPUB, the new NY library thing, new models, and so on. They are trying. So, I won't give up on them.
That said, Sony still has some work to do. It should be fun to watch.
-- Scott