I realise this discussion happened a few months ago but I was floating by and thought I'd add my two cents worth.
I worked at this school under a 6 month contract and was generally very happy with the job. Everything El Macho said in his review still applied for me in the second half of 2010, and the company is under the same ownership now so I'm guessing nothing will change in the near future. In regards to giving up your 'day off' in the week prior to holidays etc., this was never a problem. Sometimes it meant that if there was a public holiday on a Tuesday, for example, I'd end up teaching a class or two on the Sunday (my day off) instead. It really didn't bother me, and I just thought it was crazy that the kids had to make up classes on the weekend. Not really a public holiday then, is it..
More often than not, I'd do less than the contract hours. Every couple of weeks classes would magically be cancelled and I'd end up with an afternoon/whole day off. And though I did teach a 6 day week, Saturday was just a 10am-12pm class, and was easy as pie.
Overall, the job is very easy and I'd consider coming back. If you're a professional teacher looking for involvement with curriculum planning and even thorough class preparation, this isn't the position for you. But if, like me, you're hunting for your first ESL job, you're a little unsure about exactly what the job entails and whether you've got sufficient experience, Sino Denver is perfect. Plus, they provide a pretty sweet apartment
The reason they seem overly keen to hire you is because they are! When I left in December, there was only one native English speaking teacher still working there, and her contract ends this month (she's one of my best mates in the world now - the best thing about Changchun is the expat community and the way they'll look after you). The other teachers are from Russia and Tajikistan, so the school goes after anyone from England, Canada, Australia or the States like the paparazzi chase Brangelina.
The school give you money for the bus and they're really good with helping you out for internet, replacing appliances and generally will give you whatever you ask for (they'll favour any native speakers over the other staff). Make demands and they'll be met - you have the power here. I managed to squeeze a bit more out of them when negotiating my bonus, but I ended up leaving before my contract was up due to stuff going on back in Australia. They were really good about me breaking the contract, obviously I didn't get the bonus but they didn't fine me either, and there was a clause in the contract saying they had the right to sting me for 10,000RMB.
As for the dodgy English in the contract, get used to it. They're not doing it to try to cheat you out of anything, they're just genuinely in need of some English tuition. Sadly, I think the person who wrote the contract actually teaches classes.. you should now feel morally obliged to save the children from learning under this 'English teacher'. Don't worry though, you'll have an assistant whose English is substantially better.
In conclusion, I had a blast and I have nothing but kind words to say about these guys. They tried hard to make me happy and they generally succeeded. Of course, like any other boss, there were times they annoyed me. But that's why it's called work - there are ups and downs in any position you can take!