I used Thunderbird for about 10 years on my Mac laptop and every time I tried to switch to Apple Mail (or anything else) I quickly switched back. But the truth is, I have used Linux on my primary desktop PC for about 15 years now and can honestly say that it is a very pleasant experience.
I would agree that for a long time OpenOffice had compatibility issues (often no worse than trying to open an Office document on a Mac) but those days are long gone.
As a software developer and general techie, I believe that Free Software is important for my profession and for the public at large. For me, even if Linux was less convenient (which it is not - today anyway...it was more challenging, say, a decade ago) I would use it because I have serious concerns some of how Apple and Microsoft treat developers and the Free Software movement.