Yeah, Mourinho left Chelsea in a right state... Seriously? The core of players he left behind remained fixtures in their side that has been successful since he left. The meddling done by Abramovich since he sacked Mourinho can hardly be blamed on Mourinho.
Real have had an off season in the league this year for sure, but as a team he's leaving behind a very good Real side and a side that's been matching up to Barca on a regular basis whereas when he came to the club they were consistently second best and quite often played off the park by Barca.
You would have to be mad to claim that he left Porto in a bad state I think.
The only potential argument is over Inter I think, but they were already heading in the direction of aging players and short term goals. To blame Mourinho for just how poor Inter were under Benitez seems like a massive overreaction, I simply cannot think that a team would go from CL winners to that over 3 months just because of what the previous manager did.
Mourinho hasn't done what Ferguson has done, but similarly Ferguson hasn't tried to repeatedly take over teams that weren't performing and make them title winners within a couple of seasons working in different leagues with vastly different player types, teams and squads. Ferguson also hasn't had to work under the kind of pressure that Mourinho had to deliver short term success at Chelsea, Inter and Real in quite some time as his reputation at United has been set in stone.
Both are brilliant managers.