I wrote this on JET 2004 - Now it's here too!

I've been working for for GEOS for 4 months. Of course it depends on what your interests are, but I would persoanlly recommend JET (This is without yet having experienced JET). I don't hate my job at all - there are a lot of wonderful things about it. In general, if you are happy with your normal run of the mill corporate job, you'll probably like working for GEOS (or maybe one of the other eikaiwas). From the other people I've met, it seems like people working for GEOS generally like their jobs a lot more than NOVA workers. I haven't really had much experience with AEON or ECC.

Anyway....

Advantages for working for GEOS (as compared to JET):
1. Students. You see the same students every week. Some are 1x a week, some are 2x a week, and I even have a 3x a week student. Their ages range from 3 to 60 with most in their 20s or 30s. Most have a higher level of English than high school students so you can talk about more complex topics - debate politics, talk about life, sports, shopping, whatever you like. Also GEOS claims to be the only Eikaiwa that has a Taninsei system. That is, you keep the same students from week to week as opposed to Nova's system of students coming when they feel like it to which ever teacher (heresay).
Also, students in an eikaiwa tend to have a MUCH higher motivation level. Just about all of my students religiously do their homework - some ask for more. They are paying a LOT of money, so they want to get the most out of it as they can.
2. Vacation - I don't really know much about vacation time on JET - it seems to depend on the situation. GEOS has a decent vacation package. We get one week off for Christmas, one week off for Golden Week (In Spring), and we get 10 days of our choice. We also get all all national holidays off. Unfortunately though, most GEOS positions have Sundays and Mondays off. Due to a recent Japanese law, most national holidays are observed on Mondays. So overall, that's around 25 days of paid vacation in a year. We also get health care. On another note, while GEOS has its weekend on consecutive days, I've heard NOVA teachers usually have two non-consecutive days off. I think it varies.
3. Money - I think money is around the same as JET, however it is higher at GEOS after you factor in monthly bonuses. We get bonuses when students renew their contracts. Since one has around 40 students (It depends on the size of your school on how many other teachers there are) you have a few students renewing every few months. My bonuses have amounted to around US$50-120 in each of my first few months.
4. Texts - GEOS does have some rockin' texts. All of them come with teacher's manuals that have great ideas. You can use some from the book, and make some of your own. It is great having freedom in lesson planning. At an eikaiwa you ARE the teacher, make the most of it!

JET advantages (as compared to GEOS)
1. Free Time - On Tuesday through Saturday I leave my house around 10am and get back around 10:30pm. This pretty much restricts me to a schedule of wake up, go to work, come home, go to sleep - take care of all other matters and cram in some fun on the weekend.
2. Community - Working for an eikaiwa, I feel more of an outsider than I would within a school. A public institution allows one to work for an entity that is providing a service to the community, as opposed to a cold capitalist exchange. In JET you have the chance (It seems) to join the students in after-school clubs. As I mentioned, with GEOS and other eikaiwas, you do your job then go home (occasionally you can fit in an activity in the couple hours you have between class ending and last train.)
3. Sales! If you like sales, maybe this would be great for you. The main goal, above everything else, in a corporation is to make money. Every decision is based upon the bottom line, not the best interest of the students. Working in an eikaiwa you'll be expected to push books and use your status as a respected teacher to get your students to buy things. You get pressure put on you to renew your students - convince them that English is more important than anything else they are considering doing (going back to college, staying home to tend to your newborn, etc.)
4. Ethics - The previous category could also go under ethics, but this one is just for the way they treat managers. If you've read accounts where people mention their managers cry on a daily basis after phone calls to head office, yeah that's true. Luckily that doesn't happen at my school. I'm at a small school with one other Japanese english teacher and a manager. They're both fantastic people and we have a great support system. That said, my manager is still under a LOT of stress. I have heard from colleagues of the managers who cry daily. It is sad that this kind of corporate culture is supported. They systematically mistreat and taking advantage of the cultural psyche to force managers to work themselves crazy attempting to reach unattainable goals.

All of this being said, I feel incredibly lucky to be in the situation I'm in. They found me a school right where I asked to be. It is a small school, I have wonderful students, and freedom in lesson planning. I've learned how to make fun and effective lesson plans. The training helps somewhat, but it is mostly up to the individual. An eikaiwa is a great chance to get your feet wet in teaching and to figure out how to best operate a classroom (Although the classes are MUCH smaller than in a school).

I hope this helps anybody thinking about an eikaiwa as a backup.