I recently did my full ATPLs with Gulf Coast and I can not complain at all,
I went for the full time course and passed all 14 exams first time comfortably, the website was very easy to use and towards the end of my course the App became part and parcel of everyday life as you don't need WiFi to use it.
The instructors were fine, I found that some in particular were more than happy to answer questions even when classes were over and even a quick email was responded to.
I am now onto my CPL stage and wouldn't change a thing with how my ATPLs went. EFT (the school I am training at) use Gulf Coast exclusively and with the high standards that EFT have I trusted Gulf Coast also. I am now friends with some 737 drivers that used GC and if its good enough for them then it is good enough for me.
All in all I don't know if this is the info you are looking for but compared to the Prices Bristol ect are charging and the quality, I would say Gulf Coast is up there right alongside them, If any of the Management/Instructors from there read this; Its a big thankyou from me (Clue: Eyebrows)