Finally saw the Extended Cut, and I have to agree it didn't really add much.
It was a bit worthwhile to see young Hal, Carol, and Hector together from the very beginning, but frankly the shorthand flashback version already gives you all you really need to know-- and actually seems to fit the movie's zippier, more comic booky tone better anyway.
It was a bit strange to see the ring actually choose him earlier, in the nephew's bedroom though, instead of just plopping onto him in the street. I guess it had to mull the decision over for a little while first. lol
Otherwise, I still enjoyed the movie as much as ever. It's definitely comic booky, but I'm perfectly fine with that. And while the final battle DOES fly by a bit fast, it's still a damn cool one. And the rest of the movie seems to flow fine as well (seriously people, I don't understand these complaints about Hal "showing up out of nowhere"-- they clearly show the ring alerting him when there's danger!).