I would say that it is a close competition between Microsoft and Sony in my opinion ...
In my opinion Sony is a far better Gaming company but Microsoft has managed their console far better. I know people will debate my opinions so I better clairify; in any given year Sony produces a couple of good games in pretty much each genre whereas Microsoft only has a few good games that are usually in similar genres; and the uniformity of how everything works on the XBox is very impressive ... it doesn't matter who developed a game because all of the same services are still available in it.
I think Nintendo is out of the consideration because they push the industry more than Sony or Microsoft in ways that no other company is willing to push.