Windows 7 really loads faster than Vista, but the difference is just a matter of seconds. Both of these are fresh installation OS(es). Sometimes Windows 7 are lagging, specially after hibernation, but maybe that will improve once it is released with device drivers that really belong to Windows 7.
When I installed Windows 7 and checked the crossbar mode, I noticed that some files get appended with ".files". Probably I've overwritten the crossbar mode files of the Vista, with my installation in Windows 7, but it is still functional, didn't hurt except for the duplicates with extension.
One thing to consider in Vista is that, you can use Readyboost. If you are using Vaio for quite some time like me, you can just insert a Memory Stick there, 2GB will do and let ReadyBoost use it. This will significantly make your Vista Installed Vaio more responsive. If Windows 7 can have that too, it would be great plus their new feature "Bit Locker", which seems another security feature of Windows 7. I hope they release a new service pack for Vista to have some features of Windows 7 in it.