First of all, it's a Lifetime movie. They're not exactly known for creating cinematic masterpieces. Secondly, it's based on the largely untrue "memoirs" of Dustin Diamond. Thirdly, (and I'm a fan of it anyway), the original show was corny and shallow. If you watch this movie, go into it with reasonable expectations.
As far as the production value and writing, it's on the lower end of the Lifetime movie spectrum. My biggest problem is that, with the exception of Dustin Diamond, they portrayed the actors as exact replicas of the characters they played on SBTB. Dennis Haskins greets everyone with a corny "Belding" joke. Mario Lopez is the loveable but overly macho man. Elizabeth Berkley is the most intelligent, issues-driven member of the cast. Tiffani-Amber is the sweet, nieve one. The point is made that Dustin Diamond was not a total geek, like Screech, so it should be assumed that the other actors weren't exactly like their characters, either. All of them played stereotypes, so it's fair to say none of them fully fit into their stereotype IRL, either.
Given that glaring flaw, the casting is actually decent. The actors apparently only had the original series to draw upon for for inspiration, and they nailed that. If they'd been asked to just replicate an episode of SBTB, I think they would have been really well cast. The actor who played Mario Lopez (playing Slater), in particular, picked up Slater's attitude and mannerisms. As far as portraying the ACTORS, the young actors who played Dustin Diamond and Mark-Paul Gosselar are believable.
The movie feeds into the nostalgia of fans of SBTB. The original material has been debunked by the entire cast, so it's not a "true story." It's a low-budget Lifetime movie. If you go into it, with that in mind, it's a fun watch if you're really bored.
