StarCraft II is my favorite RTS. It could be your favorite too, if you know what you're getting into.
I always sucked at the game but didn't really care because it was fun. Now with SC2's ladder system I've spent a lot more time on the ladder because it's probably Blizzard's best system to date. 3/4 of my matches felt fair or close enough to last longer than 20 minutes. I'm an average player, so I imagine the game does pretty well to compensate for any level of play. The game also feels really balance, although I feel the Zerg tech tree could use more options. What really prevents me from giving this game a 10/10 is the deliberate exclusions for expansion sets. Replay hosting and clan support are features they plan to install later, probably as a means to make you buy the expansion. I was going to buy it regardless but... consider it the small blemish on the package.
It's hard to believe despite this game being out for almost two years now, that I spent more time waiting for and following this game than actually playing it. The truth is that prior to even it's BETA launch I almost knew exactly what kind of game I was getting. Most negative opinions I see on this game stem from a lack of research. There's a starter edition of the dang thing if you're on the fence of wanting to buy this great game. If you were a fan of the original StarCraft or any RTS, know that this game doesn't bring a whole lot of 'new' to the table.
What it does is refine the user interface, creates a huge story mode, and a robust map editor and ladder system. Not to mention the game has a great graphics engine, which I hear is going to be refined in later installments. People who are looking for something new should just look away, because the game is not for them. Although, if you look long enough into the custom map scene, there's surely PLENTY of new content for you to explore. People have birthed completely new genres from SC2's editor. If there's one thing that bums me out, it's that the editor is too difficult for me to use. In true Blizzard fasion, SC2 is a game you need to devote a lot of time into to get the best out of it.