How strong is Magellan? He was trusted to guard the World Government's maximum-security prison from the most dangerous criminals and pirates from all over the world, he must be extremely strong. The main reason for the mass breakout success was because he was tricked but not defeated.
Is he at par with the Admiral? Or maybe somewhere lower than that?
You cannot go by status alone to indicate someone's actual power.


   After the great breakout out of Impel Down, he was demoted to Vice-Warden. Probably because of his pride. So based on status alone you would think Hannyabal to be stronger than Magellan, which we know he is not.
 
 
 
 Well he wasn't before the timeskip. We haven't seen either of them after that, so it's hard to say where they stand now.


In the One Piece power system, it is actually hard to say who is stronger in general, since it depends on lots of factors, like who you are up against. For example, Crocodile was much stronger than Luffy, but Luffy still beat him by using the water trick. In my opinion I think he wouldn't be far off the admiral's level, since he beat Blackbeard's crew with just one hydro attack. Actually Magellan's power and ability makes him the perfect guy for the job and wouldn't be a good admiral. He would have a hard time arresting someone without mortally poisoning him.