There may be a lot of units in Supreme commander but TA spring has hundreds of units( depending on the mod you play). I prefer TA spring because it has features that Supreme commander doesnt have like 16 players per game, 5000 unit limit (nobody can handle that many units yet, but its nice to know the engine can support it). Also Supreme commander is just not similar enough to the the original Total annihilation for me to want to play it.
