The BBC is known for quality broadcasting.
Recently it's got itself bogged down in ratings wars, and of course has lost most of the decent sport. However, ("thanks to the unique way the BBC is funded" etc.), the BBC does some excellent programmes that would never be done otherwise. The natural history and local programming is excellent, but I'm specifically thinking of big programs such as The Human Body and Walking With Dinosaurs, both of which were innovative and brilliantly made.
I'm not a big fan of the bodice rippers (sorry, "costume dramas") that they seem so fond of, but in general the BBC does a lot of excellent programming that would otherwise never get made.

It get's a lot of stick, but without the BBC we'd end up with a US style TV mess, and we'd miss it if it went commercial.