Overall, I'd have to say I like the BBC, but there are plenty of things I would criticise. I'm no sure how easy it is to say it is too left wing or too right wing as it's a many headed beast and I don't know how you would sum all the parts. I do think there is an atempt to balance left and right, but I don't agree with posters saying there isn't any bias. Everyone and every media outlet is biased in some way, I know I've got my own. The BBC is riven with biases, the most obvious one for me is the bias towards London and the South East that runs throughout the organisation.
Finally, I can't say whether it is the best in the world and I'm not sure how anyone can unless they've spent a substantial amount of time in every country in the world and are able to understand all the languages in those countries. In my opinion I prefer the RTE1 (Irish) radio channel to anything on the BBC partly because there's more variety of programming on RTE1. In terms of news coverage, BBC is far too parochial compared to the international breadth and depth you get from Al jazeera. Finally, I'd say the historical dramas you get on rtve (Spain) are at least as good as those produced by the BBC.