The gameplay is deep and revolves around scouting and predicting what the enemy will do and when they'll do it. It's still very active today, through to a mod called FAF.
[1]The exception to this is the Cybran SACU, which I believe has no true counter once you take into account the gun, EMP and SAM upgrades.
Mass for mass, they beat just about every land unit including Percivals, GCs, Monkeylords and Ilshavohs.
They hard counter all air units, even T3 bombers, as their SAML can fire while (rapidly) constructing and/or fortifying an ED4 which they can then reclaim afterwards.
I just wish I had the skill to deploy them in a real setting!