@Ripplinger: Thank you so much for posting PRS+ instructions. I think I actually understand it, and you gave me the courage to download the installer. Ack! The installer won't run on a Mac (this is confirmed in the ReadMe file). Not sure where to go from here.
@eSheri: Yes, indeedy, I (the OP) have a 350, so audio would indeed be a new feature for me. And I agree with you, the addition of WiFi is a huge plus -- in fact, it's one of the main reasons I'm tempted by the T1.
@hidari: I wasn't aware the T1 couldn't read .rtf. Thanks for pointing that out. It's a bit of a bummer.
To all who have offered advice: Thanks again! You've been really helpful. MobileRead is great! I'm so glad I found you guys!