First off, let me state that I wasn't fortunate enough to watch the series when it was on tv. I've only caught bits and pieces of the series here and there and have seen the other movie. What I saw, I liked though. As for this movie, it really seemed more like an overly glorified episode rather than enough to draw me to a theatre. It seems to have been full of alot of "in" moments where a previous knowledge of the series would have helped me dramatically. I was hoping for a movie that would wrap up the entire franchise for me (considering the age of the series and it's actors), but instead got just some meh story.
The movie was well told for what it was, as well as well acted. However the writing didn't say "feature length" movie at all. There was very little of the unexplained in the movie at all as well. Mostly the dynamic of the relationship of the two partners. Rent it at best. But you'll probably only really enjoy it if your a die hard fan.