Let me say that I got my B2 in February and haven't been on the forum since March, delighted with it.
A couple of issues that arose the other day:
1) I had an album on the WebUI where the tracks never played, just ran through the titles (obviously searching for them) then started playing the next album. It took me a while to discover that I had imported them by USB as Apple AAC files and I quickly fixed that using MP3 (I didn't have the CD so this was the best I could do). I only have a few dozen tracks imported by USB so there won't be many more, if any.
I searched through the FAQs but can't find anything listing acceptable file formats, but maybe this exists and I'm just being thick...
2) I found another album that I imported from the CD. The tracks are showing up but I can't play them, with the UI or the remote. This is slightly different from the first problem in that nothing at all happens. I haven't got round to retrieving the CD from the 400+ pile upstairs but probably will, unless anybody has a quick fix. With over 400 albums imported I realise there may be a few more but this is my first negative experience. Glad I never let the missus throw the discs out.