I liked it. Odenkirk is very good. Yes, it's violent but it's also entertaining, with some inventiveness, and the action is really well choreographed.
Some of the reviews I've read here harp on the main character's "emasculation by modern married life" -- but they are missing the point. What we have here is a character study about a man who used to be someone else, who gave it all up for a home and family. He doesn't regret it, but who among us doesn't feel a vast tide of frustration well up in our souls at the thousand indignities the modern world shoves in our faces every single day? Who doesn't feel smothered by trying to be something we are not?
It's very similar to Breaking Bad, in that Walter White played by the rules and got very little to show for it. When he starting cooking meth, suddenly he found something he was really good at -- brilliant at, in fact. Too bad it was something deadly and illegal and immoral, but that doesn't change the fact that for Walter, he was suddenly in his element, and completely alive, possibly for the first time ever.
The movie is really, imho, a fantasy about standing up against a world that is always making us small and powerless, and taking control. Is it something to strive for? Not like this, obviously, but it is cathartic to watch someone else do it. And do it very, very well.