Syzygy23 said:
Both are mediocre. You want a good RTS that's easy to learn, difficult to master? Try the Dawn of War series. Specifically, soulstorm or dark crusade.
There's not much to master in DoW. They're very fun games, but far more causal then most. It's just get a deathball, and whoever has the biggest deathball wins. Really not much strategy.
And if you do try DoW OP, (Which you should), don't get soulstorm. Really, please save yourself. Get everything up to dark crusade.
But don't treat it competitively. The balance is way out the window, it's too slow, and there's no micro in it at all.