I just saw it today and i reall enjoyed it!
I can't say i thought the others were brilliant, the first had a more indie feel to it but was hugely cringeworthy at points. The second seemed a lot less amateur but lacked a certain edge. This third one i thought was much better by a huge stretch. It was a tad long, but in all fairness there was a lot to fit in. The soundtrack was good, the acting was much better and generally i thought it was just directed better, it was clear the budget was bigger and the script was less of a cheesefest! The fight scene was actually quite tense!
I have Twilight on dvd but not New Moon, i think i might actually buy Eclipse. I have to say Taylor Lautner was particularly brilliant as Jacob, and the guy who played Riley had quite a lot of screen time, he was pretty good though so i'm not complaining!
All in all id give it about 4 stars.

*The greatest thing you'll ever learn is just to love and be loved in return. Stand your ground for freedom, beauty, truth, and love.* - Moulin Rouge