Just wanted to show you some replays of me using 1GFE against Terran today:
I played all of them on EU-Ladder.
Replay 1: Close Air Metalopolis:
Openings: 1G FE against Helion + 8M-Dropship harass.
My thoughts: The opening helped me to get second gas early, which allowed me to get real big timing pushes (Colossi when he didn't have Vikings, High Templar when he didn't have Ghosts). There was no problem for me to defend against his early pressure.
Replay 2:Cross Slag Pits:
Openings: 1G FE against CloakBanshee
My thoughts: I scouted the factory and got the Observer out in time. Latter on things became STRANGE! Every terran should go and watch this replay, it's insane.
I have some more replays but they're not that special (one was vs Thor/Marine/Raven where I barely defended a 12 minute push). Didn't have the chance to test this build against Bio-Openings or heavy All-In builds. Worked well against 1 Racks FE.
I really like to play like this because it prefectly fits my PvT style (Defend in the early game, get to a macro/harrass-oriented Late-game, own the terran)
Although I have to admit that I was very lucky at scouting today! If a terran just does a decent wall-in, things are getting though.