Broly has been, since is debut, one of the most iconic Dragon Ball villains. This is despite the fact that his existence up until now has been non-cannon to the main story, as he was a movie character, and the movies before Resurrection were all considered expanded universe. It's also in spite of the fact that the movies that featured him were bad even by Dragon Ball standards.
This movie makes Broly an official part of Dragon Ball cannon. In doing so, it also changes Broly's backstory to something that actually makes sense, and makes the character himself more tragic and relatable. Whereas the original character was more of a dumbed down version of the Hulk, this Broly is more intelligent, though with a child-like demeanor that makes it clear his issues are a product of his upbringing - being raised by his father for the sole purpose of revenge.
About the first half of the movie is plot. The plot isn't going to win any awards, not that it wants to. It's just a setup for the action later, a fact that's evident by the actual bad guy's ridiculous motivation. I don't mean that in a negative way, it's a self aware plot that is pretty well executed as far as Dragon Ball story telling goes. There's no standing around talking, it's all show, not tell. That's thanks in part to the evidently generous animation budget. You'll find no attempts to save frames in this animation, which brings me to my next point.
The animation is gorgeous. Perhaps owing to the winning streak Dragon Ball has been on since its revival, the studio decided not to cut any corners with this one. The only use of CGI I noticed was a single scene animating Freiza's space ships, which was odd, but not bothersome. If it happened again after that, it was blended in well enough that I didn't catch it.
The second half of the movie is definitely the payoff. The second half, almost in its entirety, is one long fight scene. I would say more about it, but there's not much more to say. If you like Dragon Ball fight scenes, you understand. Well, if you're a fan of boxing or MMA, you understand. This is the main event, it's what you came here for. I can only make general statements about it because describing it wouldn't do any good. Just imagine any climactic battle from Dragon Ball, only with an unlimited animation budget, and a highly skilled team putting it together. That's what you're getting.
If someone said this was the best fight in Dragon Ball history, I wouldn't call them a liar. That's worth the price of admission alone, if you're a fan, or maybe even if you're not one.