Re some of the earlier posts, I'm not sure this is a pointless thread, because some of the features on the download are giving rise to annoyance, exhilaration, and anger. Other downloads which are seen as updates have not generated this degree of emotion, in my experience.
Anyway, I downloaded it, and, to a certain extent, regret having done so. Prior to downloading it, I wish I had noted what others were saying concerning that annoying side bar link to iTunes; instead, I saw all of the enthusiastic early responses. My mistake. Here, I must admit I'm not thrilled with the idea of Apple having access to my own personal iTunes library - it contains only music, but the principle of privacy applies, to my mind. Anyway, I have disabled Genius for now. It won't work on my iPod, which is a fifth generation 30 GB, and I dislike the intrusive nature of it.
I'd recommend a fifth - and sixth - category in the poll, namely, those who have downloaded and are not all that happy with the experience (and indeed, those that are).
Cheers