lol Harden being a more explosive scorer than Manu.
That's a perception given by the fact that Harden has had his chance to chuck shots as a number one guy on mediocre team. Manu even with Duncan and Parker on his team has had his more than decent amount of 35/40+ pts. Give him the chance to be almost the only reliable offensive option on a team like Harden had last season and I bet he would have looked pretty explosive getting the ball in the hoop.
To answer the question, yes, Manu at his prime is better than this version of Harden (Don't know if this is his prime yet, he's very young). It might be the homer in me speaking but I don't see a single thing Harden does better than prime Manu: he isn't as athletic, he isn't as complete on offense as Manu was, he doesn't seem to be as good as leader as Manu was and he definitely isn't as good on defense as Manu was. The one argument one could make for Harden is the durability thing but even then Harden at age 24/25 or whatever he is now has had as many (if not more) injuries than Manu had at that age.