I think I've mentioned before that I just don't have the mindset to play RTS' competitively. I'm too much of an "amass and destroy" player, and that doesn't hold up against the "lololololrush" strategies. There was a time about eight years ago when I was playing a lot of Starcraft, and managed to accrue a pretty respectable winning record of games, but I was mostly playing 3v3 Big Game Hunters.
3v3 or even 4v4 works well for me, because I have a 75% chance that the enemy is going to harass someone else, and let me do my thing. I also used to turtle off the bat with Terran Bunkers at the chokepoint which, nine times out of ten, was enough to hold off that initial Zergling assault and let me get a formidible force built up.
I tried that in Starcraft 2 and the new Terran Jetpack Marines taught me a lesson or two about base vulnerability.
What's really nice about Starcraft 2 is the replay function, which records your games and lets you watch them at your leisure. If you play against a really good player, you can go back and see what he did that worked so well. So if you're willing to watch replays of your face getting melted, you can usually learn something, either what to do or what not to do.
Overall though, I'm incredible impressed with Starcraft 2. The new BattleNET is super slick, and I can't wait for the social aspect to be integrated into WoW, as well as having Diablo 3 on it.
Starcraft retains the Starcraft feel in nearly every aspect, while delivering an experience that feels updated and fresh. I may suck at the game, but I sure do love it.