Application and driver compatibility has been a serious issue for Microsoft and Windows Vista. Not just for Microsoft, but also their many partners and retailers that are stuck with user complaints or inability to upgrade due to various incompatibilities.
Recently, Microsoft has "reassured" its partners, via its Worldwide Partner Conference, that they are working hard to solve compatibility problems across the board. According to them, their hard work has helped convert over 1,900 programs and get 10,000 hardware devices Vista Ready or Vista Capable. Of course, that may mean something as simple as a keyboard or as complex as a laptop.
While Microsoft has worked hard to minimize how bad the incompatibilities seem in the press, the effect the issues have had on the market, from enthusiast class to business class to a casual desktop user, have been obvious. Hopefully they mean what they said at the WPC, and the upcoming release of Vista SP1 will make Vista a worthy upgrade.
They really should stop using their customers as beta testers with "retail" products.