I voted ZI a while back because that's what I would have picked if both cameras were available to me and what I would have picked if any sub-$2000 RF was available to me whether with or without AE.
However, now that I bought one, I cannot get used to the feel of the camera. The VF is big, but the disappearing, low-contrast RF patch were enough of a turn of to make me miss the R2a and the rock-solid, never waver, never dim M4. Size matters, and the ZI wins in that respect, but it is not the only factor in a good VF/RF combo, and I think Leica (I can only compare it to an M4) wins.
Speaking of disapearing acts, I actually like the fading meter on the ZI, gone when looking at the VF frames, and there when I peeked left. After being used to the zen purity of meterless VFs, I appreciated not having bright red numbers blinking at me the whole time.
Finally, I'm not a pro, so I shoot for the pleasure of it, and the ZI never felt as good in use as the Leica, though the light weight felt good on my shoulder! As a result, it stays home more.