Obviously, if you're not a fan of tornadoes, or don't like intense action scenes and whatnot, then this isn't a movie for you. Otherwise, it's an alright movie for those who love to watch tornadoes suck things up, destroy buildings and throw cars, planes, concrete, etc., everywhere. I honestly expected it to be a lot worse, but it wasn't a complete blow. The acting, yeah... it wasn't that great. Many times the actors clearly just read their lines in a very weak dramatic and "scared" voice, indicating something was about to break and fall in on them, making things a little too predictable. The action itself was actually better than I thought it was gonna be, and certain scenes did look rather good, considering how close and shaky the camera was to the tornado.
I'm giving it just over a 5/10 because it slightly exceeded my expectations, given the way things in the movie looked and how it was handled. Not too many of the characters are developed all that much, except for the older storm chaser guy who can't get enough of tornadoes, which people clearly come to see his dedication to his job. The only other part of the movie that I wasn't extremely fond of was the opening scene. It's gotta be no more than 30 seconds long, and the camera gets way too shaky halfway through, so it's hard to see what's going on if you're not paying full attention (which, I don't know why you wouldn't be if it's the very beginning). I won't explain anything, in case it's considered a spoiler.
Anywho, tornado fans will think it's okay, others will say it was stupid and a waste of their time. A friend of mine said as soon as he got out of the theater that he "would've seen any other movie". That's all folks.