Awhile ago he was suspended because he openly endorsed a Democratic candidate. However, he returned from his suspension and continued broadcasting. He may not have been recently fired. MSNBC was coming under new management and wanted to change things. Olbermann left a week before this happened. It could have been his decision.
As far as his broadcasting...
I do not feel strongly. He is a bit deluded and annoyingly arrogant. Also, I like some objectivity in news and he's not objective at all.
That said he is passionate, talented, and reasonably articulate. I just didn't enjoy his show overall. It felt like a chore to watch it for more than 5 minutes. A lot of self congratulatory bullshit. He so obviously likes the sound of his own voice it's annoying.
I think he's a decent guy though and I can see how people would like his show. I'm glad he is a figure in journalism, but he's not to my taste.