I find them all equal because its like rock paper sissors.
Zerg beats terran but protoss beats zerg and terran beats protoss.
Zerg rushes hardly fail agaisnt terran because they cant place defence units around there base because they would have to sacrifice supply.
But since protoss can build photons it kills the rush and even in a long game an archon 1 hits all units under 35hp. (scrouge,broodlings.) Or if they upgrade and zerg doesnt it one hits under 39hp. But it has a reaver which pwns all ground units for zerg. Also protoss probes cant get spawned by queens and malstorm freezes larvae,eggs and zerg units.
But Terran beats Protoss because emp murders there sheilds (arbiter,archon,carrier). And also Terran basicly owns ground units agaisnt protoss. Because firebat=zealot, Marines n ghosts=Dragoons,medics=dark templar? Air units pwn all air units of toss. Battlecruiser with armour upgrades.
Bc 6 armour versus interceptor 3 damage. Wraiths own scouts because of longer attack range. Cosairs suck agaisnt valks.
Zerg beats Terran because of zerg rushes. Infesting a command center is doom to terrans. Firebats might kill lings but ultralisks are invincible when all armours are maxed. Broodlings get spawned from scvs. Lurkers just end everything to a terran. Scrouges can own Battlecruisers. Sunken colonys own most units. And hydras just shred units. Defilers plague buildings and they set on fire.
But its all about chance so I voted all equal.