Friend of mine who's a masters zerg keep saying Terran is op, so we swapped race and played 1v1 inhouse and defeated him. It wasn't that easy, but it's easier than playing terran in tvz match up. We both offraced.
When MVP streaming NA 1v1's, he had difficulty in TvZ games, but manage to barely win those games. He decided to switch to Zerg, faced ZvT and it was ridiculously easy for him to reach high masters. (Now he's a GM there if I remember correctly from last season)
DRG also said Zerg seems to be a bit powerful in TvZ.
I had a difficult times trying to get promoted to masters in euro server with terran. Stopped at low rank diamond with record around 8-8. Next season, decided to play zerg and got promoted. Was LOT easier than expected.
Main problem is the infestors. Their so called support units counters everything what terran does in tvz. Yes even mech. 3-3 upgraded mass infested terran gives very difficult time to our mech compositions in late games. Not to mention fungals on vikings to kill terrans air superiority to battle with broodlords. Sure we can spread vikings, but it's not easy as people says. Probably won't be enough to deal with incoming 15+ corruptors, infestor support, and queen transfuse + long air range attack. Gotta be very good positioned and hope for the best.
Yeah people says ghosts, but they are not effective vs decent zerg. Explains why pros don't use ghosts in TvZ matchups anymore.
Anyways, still and will be terran!!! :DD Due to micro intensive!