Supreme Commander, especially with the Forged Alliance extension is a super-tight, supe-polished game! My biggest complaint is that the devs bet on CPU single core speed continuing to increase over the years instead of trying to make their game more fully multi-threaded; even on my 5950X it can stutter in the late game.

I’ve been getting into Beyond all Reason recently, it’s coming along nicely but (to me) is more focused on emulating the Total Annihilation experience than the SupCom one:

• 2 playable factions, the Armada and the Core (roughly map onto SupCom’s UEF and Cybran, albeit with less flavor and no lore)
• T1 power generation in SupCom is via power generators (spammable) and geothermal plants (only on certain map squares). BaR has windmills, tidal generators, basic and advanced solar panels that are all spammable as well as geothermal on certain map squares
• SupCom has land/air/sea factories, BaR has bots/vehicles/planes/hovercraft/seaplanes/amphibious/naval factories.
• SupCom has 3 unit tiers that each have their own factory, plus a fourth “experimental” whose units are so big they are built as buildings from T3 builders. BaR has like tier 1 and 1.5 units that can be built from T1 factories, tier 2 and 2.5 units that can be built from T2 “advanced” factories, and T3 and experimentals are built from “Experimental” factories — and no T3 builders (!)
• much less diverse experimental units; Armada has a big walker mech and a fat lightning tank equipped with tactical emp missiles, and Core has and even bigger walker mech and a tank so slow you’d think it was immobile (albeit equipped with a commander’s d-gun).
• commanders can’t upgrade at all, and can’t even build every T1 building

The dev team is currently working on a third faction (the Legion) that seems to be somewhat inspired by SupCom’s Aeon and Seraphim.