I thought the brunt of the story was good, but much of the "future" part was sort of convoluted. I still enjoyed it. Audio was kind of random, but I didn't think it was bad.
Wolverine ages extremely slowly, so he doesn't look too much different. "Age" doesn't really apply in these movies because they don't take into account anyone's actual age or try to get them era correct. Kitty would have been much older, and Bobby (Iceman) would have been as old as Magneto and Prof X, just for starters. The funny thing is, they sort of expect you to know who the characters are, as in, fans of the comics. YET, they take every opportunity to alter the characters, change the relationships, era, alter powers, etc...
I picked up The Wolverine for $12 over the weekend and watched it. Pretty good actually, but while they kept the storyline "similar" they totally changed characters to suit the movie once again. I'd recommend it as fun entertainment for fans, just be aware it doesn't hold true to the comics just like the rest.
Last Stand is the only movie in the series I don't own now, and won't. Agreed that one was the worst without question.