Mixed reviews? Well, that in itself should be a red flag. Some people don't really care about doing a good job at teaching, so they will probably say stuff more on the positive side, or at least things like "I don't really mind". Fact is, GABA hires a lot of non-native English speakers, for various reasons and not all good. Also, learn specifically how you will get paid. I believe you are somewhat on call and get paid only for lessons when a student shows up. Also, it's not an hourly wage, but GABA has been known to advertise the pay as a "per hour" figure. So you expect X and get paid 3/4 X because you may actually teach only 45 minutes.
Some people have made fair amount of money there, but that's after staying a long time and taking a heckuva lot of lessons. I wouldn't recommend GABA or that type of teaching strategy for any newcomer. Plenty more fish in the sea here.