I worked there for about 8 months. I still fly out of Addison, but I left GTA to go back to instructing...if that doesn't tell you anything. I worked primarily in their maintenance shop, but did some MX flights for them and occaisionally flew VFR routes to build time. There is some sketchy stuff that goes on there, such as VFR only guys flying IFR b/c there are no other pilots to fly the freight. They tried to get me to do that one day and I told them NO! My relationship went downhill after that. Having worked in their maintenance facility, I saw a lot of cutting corners on paperwork and inspections. They salvaged parts off other airplanes just so it could fly a route, but didn't do the paperwork. The FAA constantly ramp checks them, they fail about half of the checks. So here's my synopsis:
1. If you like being put in a position to choose between your legality and your safety on a frequent basis, you'll like GTA.
2. If you like to get ramp checked at least twice a month, you'll like GTA.
3. If you like to fly through Texas thunderstorms with bad avionics, old airplanes and no weather equipment on board, you'll like GTA.
4. If you want to learn more about how NOT to fly in 6 months than your previous 6 years, you'll like GTA.
I learned a TON in my 8 months there, but the flying/maintenance there wasn't worth compromising my safety or my ticket.