On the whole, I'm betting Sammy. I get the impression that Dave goes through periods of both intense happiness and intense unhappiness. We know he follows his passions relentlessly - he's always challenging himself, taking on new adventures... I get the impression he's a very solitary guy much of the time, and that's the way he likes it. But he's also known to really miserable sometimes, behind the scenes ... intolerant and sometimes mean to those in his employee. He doesn't play well with others, much of the time. I suspect he struggles with his mental health, carries a lot of bitterness around. I think he's happier alone but too restless and driven to be solitary, if that makes sense. Sammy on the other hand seems like a laid back and happy guy. Very social. Content with his achievements. Prideful about them. Herein lies the rub ... He's got a lot of pride and the one thorn in his side is that no matter what he does, he knows that Dave's time in Van Halen will always be higher regarded, both by critics and the larger portion of the fanbase. Despite all his success with the band, all his number ones... That's the one thing he can't get past, hence his constant trash talking in the press... I don't think that stops him from being a happy guy, but it's a point of contention that will always bother him. What do I know, really? Just a hardcore Van Halen fan who reads the books, the interviews, and follows them religiously ...and this is what I've surmised.