A bit late but figured I'd mention this; load times seem relatively short and are generally infrequent if you don't die much. As far as the framerate there's a couple spots on the map like the big city where it dips a lot; elsewhere it's relatively stable even with a lot of bedlam going on. I've really enjoyed my time with it to this point; very relaxing game and it is possible to blow up everything within a semi-reasonable amount of time. Also it looks really nice.
You too can do ridiculous shit like this: