Alien 3 isn't a masterpiece but I commend David Fincher for taking on the challenge of following Ridley Scott's ALIEN and James Cameron's ALIENS. At the time he had only directed a couple of music videos but still he took on the challenge of continuing the Alien series what is considered one of the best scifi series to date.
To be honest, after seeing the first two you hate the writers of this film. We go through Aliens rooting for Ripley and the rest of the crew. You're extremely excited that so many characters survive; Hicks, Newt, Ripley and what was left of Bishop and then BLAM, opening scene they kill everyone. You're sitting there frustrated but you love the series so you keep watching.
I've read that before Fincher was even set to direct, the people at FOX couldn't make up their minds on the story for this film and it had been in development ever since ALIENS was released to such great numbers. One script involved a satellite made of wood that was to be a monastery. Another involved a planet inhabited by prisoners. There were many more scripts before these two, some involving genetically enhanced creatures created by Weyland-Yutani and others involved Hicks taking the lead while Ripley only made a cameo. The final film would merge the two stories involving the monastery and the prisoners.
The film isn't horrible like I said before but it definitely has it's problems. The Cgi is terribly outdated, the story is obviously muddled up. But I believe that if Fincher were brought on earlier into production the film would have been fantastic. We all know he's a great filmmaker as he's proven himself time and time again with films like Fight Club and Seven. Sadly because of FOX and their meddling confused hands Fincher actually disowns this movie completely.
But there are good things about it. Besides the cast, which of course includes the return of Sigourney Weaver. Newcomers like Charles Dutton and Pete Postlethwaite bring credibility to an amazing cast of familiar faces with no names. Actors who you've seen before but don't know their names, this cast is filled to the brim with character actors. The film also looks brilliant on Bluray and the special edition version has some plot holes filled and miniature tidbits that gives the film more meat.
All in all I believe the film is a perfect ending to the Alien series but sadly gets ruined by Alien: Resurrection, a film no one asked for. It has even more problems than Alien 3, but is a fun watch when you have nothing else to do. Stick with the first three and you'll be okay. Fincher did the best he could with what he got, made lemonade out of his lemons and what more can you ask for from him.