Personally I think ITV do the best overall coverage, especially if you're watching the full stage (though a six hour broadcast will include about an hour of ads). Daniel Friebe is easily the best interviewer. However, Ned Boulting is really not great at calling sprints.
I'm really not a fan of his work, but Kirby is the best at commentating a sprint finish. And, to be really controversial, I think the Liggett-Sherwan duo in their prime were the greatest. The genuine excitement and urgency they brought to stages was terrific, whereas the likes of Rob Hatch often seem to create artificial drama. Above all was their chemistry, when they could bounce back and forth without messing a beat. Nowadays Eurosport have so many different pairings where the commentators don't seem comfortable with one another, and too many awkward pauses.