Cuthbert is the best in the business IMO.
I'm more concerned about play-by-play over color. A good pbp person can do both.
Color defininately adds, but so does the in game reporter (I do like Millions in that role).
Play by Play at a high level is tough, the system is set up that you call a local broadcast, be it a junior team, minor league or even the local tv or radio broadcast of an NHL team. Then if you make the leap to national TV all of a sudden you have to be impartial.
For disinterested teams that's not so bad, but your childhood favourite team or the team that you built your career with would be tough. Look at Hughson, one of the best EXCEPT when calling the Canucks. Why? It's hard to turn off, especially having been trained that a Canuck player in the box = PK and opposition player = PP.
This doesn't really get to the crux of the topic, but I like to babble while enjoying my morning coffee