I just got back from seeing Twilight with my husband & daughter. If you read Twilight, there is no spoilers because it's exactly follows the book. If you never read Twilight like my husband, it is very teen orientated & very slow especially the beginning. I think because they wanted you to really feel the love story developing between Edward & Bella. I whined about the actor playing Edward, now I just love him. Bella was perfect. Visually, it was a beautiful beautiful movie.
So bottom line, if you read & love Twilight, you will love it.
If you haven't read Twilight & are older than 18, you will think it will never end <G> & was painfully slow.