This is a late reply, but I'm hoping it will serve as a warning to anyone considering working for them. I worked for them for six months as a teacher in a local school and my overall advice would be to AVOID them like the plague. They're little more than glorified human traffickers. Here's some of the things they've done to me alone;

They'll rip you off, taking well over 50% of your paycheque. I have it on good authority (several disgruntled Chinese employees that have left the company) that each school pays Echo 13,000 RMB (£1,393 or $2,000) per month. The teachers see 6,000 (£643 or $923) of that. Every other foreign teacher I've met has been literally astounded by a contract and wage that bad.

Within a couple of hours of my stepping off the plane, one of their employees started sexually harassing me. She kept touching me inappropriately (squeezing my arse etc), making suggestive remarks relentlessly, even when I told her I had a girlfriend. You may not bat an eyelid at that, but imagine if the genders were reversed.

They're encouraged by their manager to lie to your face. When they told me where my school would be, they told me it would be in Taizhou and there would be other foreigners, expats and Western comforts there. Instead it was Tiantai, a town in the middle of nowhere and I was isolated as the only foreigner for a hundred miles. I've never felt such crushing loneliness in my life. When I forced my way out of that school, they tried the same trick again, telling me the replacement school was in Wenzhou, when instead it was hours away in Yueqing.

When I was in Tiantai, in complete cultural and lingual isolation and genuinely considering suicide as a result, they flat out refused to find me another school. They threatened to fine me $1500 and blacklist me from ever teaching in China. They were both empty threats, but I didn't know that at the time.

I managed to get round that one by teaching badly on purpose (sticking a movie on as soon as I got into class). When that happened, they stopped paying me and one of their employees called me 'an asshole'. I didn't want to resort to that, but I was genuinely concerned for my own mental health due to isolation and lack of human contact (I had some weekends where I was too depressed to leave my bed). As far as I'm concerned, they forced my hand

It stipulates in the contract that you sign that Echo will pay for your working visa for a year. They don't. Instead, the schools cover the cost. I discovered this when I got my passport back and the visa in it was only valid until February the 8th. The school in Tiantai only ever had any intention of hiring me for one school semester, so they only paid for my visa for that amount of time. Because of Echo's penny-pinching, I had to leave China during Spring Festival anyway. A blessing in disguise. I've found work in Vietnam and have never been happier.

These agencies will try and make you believe that your services are worth very little; they'll probably tell you that there are loads of foreigners going for the same job as you (there aren't), that you don't have enough experience (the schools don't care) or that foreign teachers don't make that much (they really, REALLY do). Even if you have no experience whatsoever, you can still get a job in Shanghai, earning 13,000-16,000 RMB a month. No matter what bullshit agencies like Echo tell you, do not settle for anything less.