It is your standard generic super top secret group of people who deal with alien sci-fi show that just happens to take place in the Doctor Who universe. I watched the entire series and don't regret it. Only two short season and the special everyone always gets all excited over. The series wasn't all bad, and I dare say I kind of enjoyed it at times. But at times it went way out of the way to push the bisexual stuff. Out of the main cast, the one character who isn't implied to have done someone of the same gender during the course of the show is shown in an extended make-out scene with another women.
It felt like they were trying really, really, really hard to please the gay community, but it just came off as over the top, unreasonable, and immature.
The Scooby Doo comparison has never made sense to me. Sometimes I think it mostly came from people who never watched the show. It is more like less silly and more casual Men-in-Black than anything.