Hmmm...
Well, it lives up to the hype. It's very big. Once you know a build order, you can actually make the game go faster...but faster is not as fast as other RTS games. I find the games are more tactical the way I play instead of strategic anyways, despite what they say about being strategic instead of tactical.
You always play zoomed out (or so I do). Some people are big fans. I can't say I am. Since I'm not a huge fan, it's hard to really give it a fair review.
I'd say to give the Demo a shot. The Demo is actually a good representation for a taste of what the rest of the game is like. If you REALLY enjoy the Demo, you'll probably like the game. If you like aspects of the Demo, but get bored (like me), you MIGHT enjoy the game, but be aware that if you think the demo mission is long and get's boring...well...you just MIGHT get bored with many portions of the game's campaign. If you don't like the Demo...it's a good gamble you won't like the game.
The game has some rather awesome ideas, and is great for what it sets out to do. It DOES live up to everything they said it would in my opinion, however, I found that after the Demo for C&C came out, and I tried it...I ended up playing a DEMO (C&C3 demo) MORE than the full game of SC. But that's more of a speedy high and fast game vs. a build up game with hundreds of troops.
I think the micromanaging of SC with that many troops is what turns me off...but for many people, that's what turns them on.