Neither the Windows or Mac versions are "out yet".
The Windows version is still in (late) beta. The MacOSX version is possibly in earlier stage of development.
Patience, grasshopper. Patience.
I'll assume that you mean that windows version of TL2 also is full of bugs then ? Oh well, so was the Diablo 3. Actually, anyone who was able to play during launch and notice the bugs was happy - most people could not even connect.
Now, I would say that this thread's title has become a bit of obsolete by now, as a new game stands between those 2. Path of Exile is on open beta, free to get, free to play. Most of my hopes are on this rather than D3 / TL2 debate.