Took me a while to figure out the @ symbol as well, which you may need for the "." as well.
I still have not had a chance to hook up a usb drive to the receiver. I suspect that navigation of songs and folders will not be "easy" or "quick", but who knows. I stream my Mac itunes to the AVR which contains all my CDs (over 600) ripped lossless. Sounds great no hiccups, can use ipod, ipad, or iphone to change songs etc.
I have really been impressed with Pandora. Navigation is ok and the new stations I set up online show up very quickly. no hiccups from pandora at all. I have not tried slacker or an other net radio yet, but suspect similar performance.
Overall, this thing has been a dream. Great PQ and functionality. I have set up with 5.1 and powered zone 2. Zone 2 has worked flawlessly as well as the HDMI pass through when the AVR is off. I can pass through a signal to my TV without the surround on while having a separate audio source playing in zone 2. I can't comment on switching delay between non-hd sources, but do notice a slight delay (1-3 seconds) when turning on any new hd source -- I chalk this up to the return audio working and figuring out the delay...which I have not experienced any sync problems at all.