I bought that one too, it's really great!
Another great thing about the game is the possibility to download and watch other people's replays, I love watching big matches between very good players, and I learn new tactics that way too.
I can't wait for the Directx 10 patch though, it should speed it up when playing huge maps with a lot of units
If you didn't like TA, you might not like this one either... but maybe you should try the demo.
Command & Conquer 3 looks like it'll be a great RTS as well, although they are very different, so it's not a waste to get both.
Concerning the replays, I know C&C: Generals had that possibility as well, but many other RTS don't, that's why I wrote about it (I didn't say it was a new option that was never seen before, just that it's something I like).
SC brings a whole new meaning to strategy gaming. You aren't restricted to the fixed scrolling camera. You can truly manage your forces on a micro-macro scale. It has a very advanced waypoint system, tells you how long it takes for this to build, to get here or there.... it feels great to have all this information, and actually MAKE USE of it.