Used Quickbooks for a few years now, does everything I need it to do and a lot more, the payroll is excellent and another big plus is you can run upto 10,000 businesses from the one software package, unlike Sage which will only run one unless you buy the multiuser licence.
You should be able to do a straight transfer from Quicken to Quickbooks as they are both designed by the same company Intuit, the best thing to do is ring them and talk to them.
You may also be able to get a "patch" from them that will upgrade your edition of Quicken software to vista compatible. I get updates sent every year from Quickbooks and from 2006 all their software was vista compatible.