I think that he's going to fit in just fine with the Patriots, both in the locker room, and on the field.
In football, desire is an important part of overall success, as is the ability to suppress the ego in order to boost the overall team's success. He can do both.
But just as important is overall happiness. A player can suppress his personal feelings, his frustration with losing, with poor situations for only so long before they begin to affect him either in the locker room, on the field, or both. It's human nature. But put a player into a positive situation, a place where he's happy to be, and he will usually thrive. I'd even offer the idea that a positive situation helps injuries at all levels heal faster. When the mind isn't dealing with emotional/mental pain, it can send those resources to deal with physical damage.
But I'm happy to see Sopoaga in a Patriots uniform. That doesn't mean he'll succeed here, or that his presence will help the Patriots get better, but it certainly won't be a distraction, and he has the athletic and mental skills to be solid player on the Defense.
I thnk that this is a VERY good move by New England and that he'll turn out to be well worth the cost to acquire him.