I have been using Win7 now for a few weeks and I have really put it through it's paces. I have decided I like it so much that I have upgraded every workstation or laptop in my possession worth using to Win7. I also have a few little tweaks that will add some familiarity of XP and Vista to your Win7 installation...look for them here soon. (hint: Quick launch bar and disabled services)
If I had to give a simple answer on how Win7 stacks up, I would have to say the it has the eye candy of Vista and the performance and stability of XP. So far, and as I have mentioned before, the only Reservation I have is IE8...it's total crap. I work with Sharepoint A LOT, so the single sign-on afforded by IE is pretty much a must, but if it were not for that it would be Firefox or Chrome, without a doubt. IF you can deal with a non-native browser (and most people prefer to), then consider moving to Win7. It is much lighter weight than Vista, and before long XP will no longer be supported. You can actually use older machines to run Win7, ones that Vista ran like a dog on, provided they at least meet the Win7 minimum requirements.
All told Win7 is a hit. Microsoft needed to hit one out of the park after the Vista debacle, and this one is outta here. Users can finally be productive again, IT staff can quit fretting about an out of date OS and how they will keep it safe. CIOs can finally get on with the budget and focus on enterprise apps rather than on what they should do about desktop deployment (sit and stay or jump and gamble).
Yes, the verdict is in: Windows 7 is your next operating system. Get up on it.