It's very much a taste thing. TA-likes are a whole different kind of RTS and demand a different type of skill. SCs reward quick thinking whereas TAs seem to much more reward overwhelming scale. I can usually counter my way out of a problem in SC, but in Planetary Annihilation if I've committed in the wrong direction or just not made as many mines as my opponent, I'm sunk.

Also there is the number of units. Over three hundred in this game! TAs tend to have lots and lots of units whereas the other shall we say branch of RTS design tends to have far fewer.