First off, I want to say that I know it's beta, and I know that "by definition" that implies that it is imbalanced. Having said that...
The Terrans seem OP to me.
- The Reaper is ridiculous. The thing is available early, it can jump cliffs, it's fast as hell, it's strong, it can harass your eco big-time, and to add insult to injury, it has a ridiculously strong special ability against buildings, and can take them down in no time. The effort required by you to counter this thing early game is not matched by the ease with which the Terran player can deploy this thing and harass your eco to death, as well as take down buildings.
- That Hellion is a nasty early harass unit too. It is strong against early light units (i.e. probes, drones, zerglings, basic infantry) and it is fast as hell. I mean, between the Reaper and the Hellion, the average Terran opponent can kiss the game goodbye.
- Marauders just seem overly powerful to me.
- That EMP shockwave from the Ghost just seems to royally fuck Protoss.
Protoss seem UP to me.
- The Stalker seems too weak in terms of hit points and attack (they drop like flies to Terrans), and blink seems to take a long time to recharge, where as Terrans just seem to spam the hell out of their special abilities.
- The Collossus just seems to be a totally underpowered hunk of junk that auto-explodes every time an enemy unit gets within sight range. I mean, they pop like helium balloons. Weirdly, they seem to have nerfed it even more with their last patch, where as if anything it needed a substantial buff.
I mean, the only time I see a Protoss or Zerg beat a Terran is if the Protoss/Zerg is just a way better player.