Assad has all but won. From the Telegraph:
The last remaining rebel fighters in Homs have been evacuated by the busload, under an unprecedented ceasefire agreement that dealt the final blow to the opposition in the Syrian city once described as the “capital of the revolution”.
After nearly two years of government siege, hundreds of weary rebels abandoned their last stronghold, the heart of the revolt against President Bashar al-Assad, handing him a symbolic victory weeks before his likely re-election.
The cost has been tremendous, in lives, in money, and in geopoliticcs. But he's still standing. Iran has gained - but so has Israel, at least to some degree. Of course, given that we're talking about the Middle East, things can always change - and certainly will.