I tested the new FL Studio version on elementary OS Freya (32bit). This distro is based on Ubuntu 14.04, so you should see the same results on Ubuntu too.
I installed it into an already existing XP bottle with some other software, so I'm not really sure what requirements are needed, but the bottle has the core fonts, NET framework 2 and 3 and visual c runtimes installed.
The installation went without issues and the app works just like it does on Windows. Compared to FL Studio 11, it's even better, because, finally, we can play & use REX files inside it. I don't know if it's the new Crossover version or the new FL Studio version, but something fixed that issue.
External samples work fine, the built-in plugins work fine, exporting wav & mp3 files also works. It also looks beautiful, as you can see from the shots. The only issue I had was with switching to other apps. Alt+Tab doesn't work, it defaults back to FL Studio, but only if 'Allow window manager to decorate the windows' is checked in Wine configuration (Bottle - Control Panel).