Being Norwegian I obviously don't watch or listen to everything the BBC does, and as such a lot of my opinions on the BBC are probably coloured by my opinion of our equivalent NRK.
But, I don't have to watch, or even like, everything they make in order to appreciate that their business model results in a lot of programming no commercial channel would take the risk to produce. Planet Earth for instance. I don't believe for a second you'd see a huge production like that if it wasn't for the BBC, and my god what a beautiful thing.
At the other end of the scale, NRK a few years back produced a series on the Norwegian language. Hugely boring topic, and certainly not something that draws people to the screen, but if you actually tuned in you'd discover one of the most witty and interesting programmes I've ever watched on Norwegian television.
Furthermore, I believe that the fact that the BBC doesn't have to answer to advertisers is one of the main reasons programs like Top Gear can be given such free reigns when reviewing cars. A commercial channel depending on ad income cannot afford pissing off advertisers to that degree on a weekly basis.