i'm all 3. They are all capable of failing in various different departments. I prefer OSX for "day to day" usage however.
ZX-Spectrum 48k (not really mine though)
ZX-Spectrum +2 128k
CD32 + SX-1
Nindendo Gameboy (Original)
Amiga 1200 - was upgraded to 030 then downgraded back
Amiga 1200T 030 (a different machine)
PC with Windoze (dont ask me what spec)
PC with Windoze XP - 1ghz Intel
Macbook 2.2ghz Dualcore
Nintedo DS Lite
PS3 (with Linux installed)
At some point after the second PC i put the Amiga's 030 back in the normal case a1200
I havent listed where i've had the same machine with lower (or same) spec twice, or where i've picked up "spares" from unwanting owners.