i haven't tried playing against terran yet with protoss but I think it's a pretty even match up, high templars are so good against any race, PvZ I think is so much better since it feels more balance unlike that in TvZ were I can just go marines+tanks and it's GG for zerg.
Man, I hope i didn't switch to terran when I play protoss. But since I saw that there's a lot of protoss here in my country. That's the time I played terran. Also I think I suck at PvP.
The only thing I found out that's kinda imbalance with the PvZ match up is the Broodlords, I can't think of any unit that can handle BL and hydra combo. Maybe a few stalkers blink with HT storms will do the trick but that's too much minerals/gas.
I might switch to protoss again if ever the time comes, but as for the meantime I'm in love with terran since boxer's back!
edit: I feel like an idiot with the too much minerals/gas.. well you'll have a lot of minerals/gas once he gets broodlords if you have a 3rd expo.