I regularly buy a new version of Codeweavers' CrossOver Office, which is a commercial version of Wine -- a package to run Windows software on Linux. All their code is open source, you basically pay for support and the fact that Wine is repackaged in a user friendly way, with an installer, help files, et cetera.

They have an online database where applications are rated for usage. Each application has one or more "advocates", who maintain the usability status for the app. I've become an "advocate" for Enterprise Architect, an excellent UML modelling package.

The short story is that EA runs pretty well on Linux. They even have a webpage dedicated to running their software using CrossOver, and gave an interview on this subject. I've had a crash once, and some widgets aren't drawn correctly, but for the rest it runs pretty well.

If you're still interested, regularly check the CrossOver Enterprise Architect compatibility database entry because I'm planning to keep it up-to-date with tips and tricks.