I've got a 10v. When I had 10.5.8 on it, my Dell booted extremely quickly, but never reliably, so it sometimes needed 10 reboots to get me into OSX.
I've now got a 10v with 10.6.1 installed. It boots every time, but I find it takes noticeably over a minute to boot, and when I started a thread on this a while ago I didn't get any suggestions as to what might be causing it or how to improve it.
So I'm thinking of dual booting with Windows 7 but given that I've never seemed to have adjusted to OSX all that well, I'm thinking of just wiping the slate clean and going with Windows 7.
How much faster does Windows 7 boot for you, and how much better is performance if at all? Does video play smoothly unlike OSX? Does Intel Speedstep save much battery time on a 3 cell unit?