[jasonbvr]

To actually answer the question, in most cases the smaller the company the better the treatment of the employees. Now I can't exactly give you a 1-5 of the top ones, but I could probably tell you who are the worst of them.

Before that though, a big thing you must first realize about teaching abroad is that everyone has a different experience. I will concur with the general consensus that JET is the tits, but I know more than one JET ALT that hates his or her school for varying reasons or the town they are living in. A trouble is personalities clashing. I have worked with countless teachers, Japanese and foreign, who I couldn't stand.

Anyways, as far as companies go the best way to test them out is to actually talk to the cog in the wheel you're replacing. If the cog is missing already or not wanting to talk to you, that could probably be a sign of what to expect. But, then I have to add this disclaimer. The guy/gal could just be a total wanker to begin with and the company actually nice.

Anyways, the absolute last choices on my list would be Shane's and Heart. People rail Shane's all the time for dealing out split shifts, 9-10 then 14-18 for example, and not reimbursing for travel expenses that should be covered. Heart is just plain cheap. I wouldn't take anything less than 240,000 for ALT work. They try to sucker you in too saying that since they cover a lot of your utilities you are making comparable to other ALTs, not true.

Better companies. I have never heard complaints about Geos and Interac. Some of the teachers I knew from Interac were whiny, but I think there displeasure was misplaced and should've been directed at the schools they worked at. I've heard mixed reviews of Borderlink and RCS, the two big ALT providers in Kanto other than Interac and Heart. Gaba seems to be decent if you can get attract enough students since they choose you as opposed to the company assigning them to you. That is about all I have to say about the big players, but I still would go for a smaller operation given the chance to do so like Fifth Wings who are my former employers.

Hope that helps.