GABA is the kind of program that's not going to hold your hand. Some people, especially those coming to Japan for the first time, may find that daunting but for a certain type of person it works very well. I liked that GABA didn't tell me what flight to take to Japan, where to live, or when my days off were going to be.
So if you're independent and motivated, this kind of program would suit you.
The pay is based on how many lessons you teach in a month, so you can make quite a bit of money once you're established as an instructor. The flexibility of the schedule also means you can plan time to travel / go on vacation / entertain friends visiting Japan, or work on side projects: a lot of other instructors I know are musicians, artists, freelancers, etc.
I really enjoyed the one-to-one teaching style, which I personally find less stressful than a classroom environment. It gives you more opportunity to strike up a meaningful conversation, get to know your students (or as we call them, "clients"), and meet interesting people.