Most of the problems came from people upgrading their old pcs to Vista when Vista first came out. There were problems because the machines weren't powerful enough to run it; some of the drivers weren't compatible and Vista itself was a bit 'buggy'.
Those bugs have mostly been ironed out, and you should have no problems with it. Check to see if your printer and other peripherals are compatible with Vista, and if not, see if drivers are available online.
Vista is a different operating system and will take a little time to get to know - get yourself a good book to help you in the first weeks, your local library should have a selection.
Make sure your new PC has at least 2gb RAM.