Pros
Salaried position. High salary for Eikaiwa job, about 30,000 USD depending on a 1:100 exchange rate. Intensive training for adult classes: cover theory in one day, then application over 2 days where you have an experienced teacher give you tips. The lessons and everything are given to you. It's all actually easy to get into the flow. Employees, even trainers, are every open and honest in my experience, you could tell when they had to say something was company policy because they made it clear that was the rule.
Cons
Kinds training is about 5 times more than adult lesson training and has a ton of prep material, plus is a hectic room, so no hands on training is not good. The work is intensive and you are under a tight 10 minute to wrap up a lesson, change material, log notes, open up next student info, plan a lesson they aren't doing that day, and get to the room whilst doing any lobby service/talking if needed. Plus no snacking time, little chance to use toilets, shorter than average lunch break (prob 40 minutes here depending on class prep time you want) or get water make for a very draining day if you need those. This can be very exhausting work and will probably drain you more than you expect which is a hurdle at the beginning as a constant thereafter. And yes class prep time is needed because the students will review you and if you do good you get a bonus, if you do bad you're probably not going to hear about it (branch staff must tell you) or if you do it will be without constructive criticism.