While I realize you can't support beta operating systems, the whole point to the beta is so that developers can test their applications against the next version of the OS and have most of their issues worked out by the time the final release happens.
As a counterpoint, life is too short to develop against unstable APIs.
I've seen too many things break between the final developer version and the RTM version. OS companies lately seem to treat a "release" as a feature freeze, like a beta before Google ruined the term. As a result, I know plenty of companies that won't even start testing on a new OS until it gets released. Until Apple, Google, and Microsoft start producing more stable (in the API sense) releases, I can't say I blame them.
