When I saw the first one, I thought the "twist" ending was quite stupid and non-sensical. I was skeptical going in to see the sequel, but it being Halloween weekend, and having already seen The Fog, I thought it would be worth a shot. And as it turns out, it is better than the original, by far. The acting is actually pretty good, especially considering that most of the minor characters (the people locked in the house) are relative unknowns and that their characters require them to overact and be hysterical often (which usually results in acting performances that are nearly unbearable to watch). The end twist was clever, and hasn't entirely been done before, and the tension and fear were definitely present while watching, even for someone like me who rarely gets genuinely scared or even uncomfortable watching a movie. Two things I didn't like were 1) that the traps didn't seem, well, "trappy" enough, so most of the deaths weren't so much clever as resulting from an act of stupidity, and 2)as in the first Saw, the gore that the trailers promised, sepecially with a tagline like "Oh yes, there will be blood," was severely underrated. I didn't come to see Saw II so I would miss the actual spiked club going into the back of someone's head and then see them fall facedown on the floor and see a pool of blood seeping out from somewhere underneath them. This is one of the cheapest ways filmmakers can show someone dying without being too graphic. But then again, there's an uncut version of Saw which I haven't seen yet; hopefully there's more gore in that version, and hopefully there'll be a similar version of Saw II when it comes out on DVD.
Definitely worth your money, and if you like to gripe about the price of movie food, here's a tip: don't buy any. Believe it or not, there's no written rule that states you must eat food while watching a movie. Try it sometime. I guarantee you'll survive.
Oh, and I think everyone should watch the downloading movies / piracy talk. Mods are watching, and they're notoriously harsh on users who post about this stuff...