The best game in my life.
While you can put aside a good 30 hours to finish the campaign, I spent ONE FULL YEAR ENJOYING it, completing every skirmish on every difficulty with every variation of enemy factions and numbers, till I tried everything and make silly maps out of the editor and play some more... I'm a fan(atic).
Anyway, you really have to play it with a mid-90's mindset to fully enjoy the masterpiece and forget about any high end 3D graphics for a while, then you would understand why gamers salute it.
KingLim