While I'm not much of a statistician, I figured I'd take a bit of a look. Some random findings looking at the last 3 months:
Looking at 2200+ elo with a +/-200 elo advantage for the winner (still kinda even skill) Just about every factory is viable somewhere, with a slight advantage to Shieldbots vs Any (55-45), but overall everything is fairly even. Spiders was surprisingly viable against Rovers, though.
Looking at ~1600 elo (the biggest elo block on the histogram) with a +/- 200 elo advantage for the winner, Rovers have a 75% chance to win, while Shieldbots, Amphbots, and Tanks also have an advantage, while Hovercraft doesn't work (probably because Daggers take a lot of practice to use well).
At the highest levels Shieldbots become quite reliably useful, but everything is overall still pretty close to 5-5 matchups.
The first 3 months of stat collection also show much stronger matchup advantages along all of the above lines, so I guess the matchup stats present a positive trend in game balance.