Okay. I love this movie. I saw it twice in theatres in 3D, forgot to take pain medicine, got a headache both times, and it was worth it. Of course, I was mainly going for the special effects, but hey, the rest of it was worth it too.
Tron: Legacy is one of those sequels that you don't really need to see the original to enjoy, but you have a better understanding of what's going on and the importance of names and events if you do. Also, you can chuckle at the inside jokes and references that they work in.
But then, I'm one of those that insist in watching things in order, so I'm a bit biased. Honestly though, this is a good action-based movie with a fairly solid script. I want to say a good, solid script, but I'm also mindful that I am biased about this. I like the acting, I like the music, I like the dialogue, and of course, I love the special effects. Like the original Tron movie (for its time), the computer graphics and special effects in Legacy is just awesome, and suits the 3D medium perfectly. Not that it's not enjoyable in 2D, but in my opinion, this is how 3D ought to be used.
What I also is like is how the romance in it is kept to a minimum, if it could be called a romance at all. Which is kinda refreshing, especially coming from Disney. I won't argue/discuss feminist points, or potential meanings of free/share-ware vs commercial software here; so let me just say that for the thinking types, there's some brain food for you in Legacy as well.
So, for wrap up: good plot with a lot of action, good acting, and awesome effects. To me, this is a good movie for the family, for action fans and even for the thinking people in the audience. Have fun!