The Transformers: the movie was an animated feature to help sell the toys... i mean tell the remarkable story of the conflict between the Autobots and Decepticons...
The film is notable for some of the actors who lent their voices to the characters, especially Orson Welles who voiced Unicron. Amazingly this was the great man's last role. Other stars who you can hear in this film are Leonard Nimoy, Casey Kasem and Eric Idle. Not many films can boast that kind of line-up!
The story itself is decent enough with nothing too innovative. The film flows well though your attention may wander after a while, what works as an half hour long TV episode does not necessarily translate into an hour and a half long movie. A problem with the film, i feel, is that it was too much like the TV series...
Visually however it is still a treat and the soundtrack... well if you like late 80s US heavy metal then you'll love it. Otherwise you may want to bring ear plugs. Personally i love it and own the OST too.
Overall its a decent enough animated film. Maybe it didn't work as a movie that well but it certainly was light years ahead of the endless CGI-fests that are the Transformers movie experiences today.