My 235 is the '73 Charger, and I've been glad for the extra room in the back when I've had passengers back there. I've found the performance of the Charger to be good enough even in the summer here (my weather is essentially the same as Nick's Las Vegas), but I haven't had a need to go to Flagstaff at the hottest times, for example (DA there can get over 10,000). I rarely need to load anywhere close to gross, so the fact that gross is pretty high gives me some elbow room when it's hot. A Dakota would definitely perform a bit better here, but there wasn't one in my price range when I was looking, and I've been happy with the Charger.
I believe it's 2000 hours on my O-540-B4B5. If some owners are claiming they went 2,500 hours or more, well I definitely believe that, but it's past what Lycoming recommends.
