"About Face" is not really a bad movie - it's just not as good as it could be. It is a remake of a movie made in the 30's called "Brother Rat", which was based on a Broadway play. "Brother Rat" is a better movie than 'About Face" as it had a better cast and a more subtle approach to the comedy angle; "About Face" is somewhat heavy-handed in this regard.
In my opinion, what really sinks "About Face" is the forgettable musical score. For some reason it was decided to remake it as a musical, but the songs are very ordinary. The songs are trifling and unmemorable, except for Joel Grey's number. And a reviewer above is right about the closing tap dancing number. It was a show-stopper, but the show was over.
I saw "About Face" when it first came out. I was 11 and I loved it, and saw it several times. Funny how time and age can provide a different perspective. It is harmless fare and entertaining to a point, but sometimes a substantial time lapse can lead to disappointment.