I think that these two have very similar football mentalities and thought on what wins football games.
I think where the big difference lies is in something that can't really be taught and that is personality and player relations.
I look at Belichik as the misreable BP, obsessed with being the best at all costs... great football mind.. demands a lot from his players and gets them to play at a high level by setting that as the standard.
I'm not sure that you could say that one is better than the other... even if they coached the same team.. I think they are just different.
I think I would personally rather play for BP though... because of how he treats his players.. you can tell players respect the way that they are treated, because BP seems to have a true interest in the development of the player and will be brutally honest about their situation with the team.
So Belichik.. great football mind, very hard worker, great strategist...
BP.. vast knowledge, uses his personnel well, better coach...
I see Belichik being more X's and O's and BP being more fundamental.. one tells you what to do, the other tells you what you are trying to accomplish.
Both can win you a superbowl.