Same for me. The difference in performance is so huge, I almost can't believe it. Vista just never worked right on my laptop, probably due in part to some of Lenovo's less than stellar drivers. And, to be fair, I never did a clean install of Vista. I went off the factory preload, which almost certainly contributed to the poor performance I saw under Vista.
It so happens I don't have any desktop machines so I can't "evaluate" W7 on one. So for that reason I should be denied the opportunity to enjoy and asssess W7 on the machine I do have and use??? I really don't think so.
Since my "evaluation" is for my personal use, I don't see why I shouldn't undertake it in any manner I feel like. My laptop may not be the most powerful thing around but it is x64 w 4 GB ram and is running super fast/well on W7.
What I do have are a bunch of extra hard drives lying around for my laptop, so what the hey is wrong with installing W7 on one of them and checking it out. Once I did that, loaded up my stuff and saw how wonderfully it was running on my system (as in better than it ever ran before), it was a no brainer to switch to 7127 for my main OS, mission critical stuff and all. I hope I never have to boot into Vista again, but of course, I have my old set up on it's own hard drive put away in case I should need it for some reason and I have several backups (both clones and images) of my current 7127 installation, so I'm perfectly comfortable testing, evaluating and using this wonderful OS (on my laptop or whatever). It is running everything I "need," in almost all cases, better than Vista did, including some programs with unsigned drivers like PG2 (had to test sign them myself).