Vista is better than a pirated copy of Windows 7. (If you can't say something nice about an OS, do not say anything at all).
I've been running Vista since the first public beta and I have never found it to be the pig some people claim it to be, and thus have nothing bad to say about it. In fact, I quite like using it... especially in 64 bit and the way I have it set up to suit myself. I'm using Tweak Vista to eliminate the annoying quirks of UAC, for example], and for me it is more than just usable. As stated above, I found little or no difference in performance between Vista and Win 7 on this machine... though I'd say the recent addition of a SSD would have upped the performance of Win 7 somewhat.
Why dual boot between Vista and Win 7? I like to keep Vista on my rig for MS Office, Photoshop, PSP and other art/photo manipulation programs, and Win 7 for music and video editing, etc. Hence I've not bloated either OS with too many programs all at once and therefore keep a sleek fast machine with fewer registry nightmares.