Hey there smorriskc. I know this topic is a little old and chances are you aren't even keeping up, but on the chance you will look back here I thought I'd post my two cents.
I'm currently teaching in a hagwon and it's really just like any other job. It's been my experience that the guys over in Dave's tend to be overly negative when it comes to hagwons. Sure you will work a little (or a lot, depending on how lucky you get with your public school posting) more in a hagwon, but you will also get paid better. Not a whole lot, mind you, but enough to offset the fact that you'll be working maybe anywhere from 5-10 hours more per week.
Most of the horror stories you here about people working in hagwons are people who didn't really do their research and went for an ad that said "3.0 million + housing!!" only to find out they are working for a small mom&pop school. This is a really risky situation, cause you are basically stuck when it comes to your pay/job security/hours. If you go with a larger company (like Pagoda/YBM) you will be very secure, have contracted working hours, breaks, and will be paid at a set time every month (in my case on the 7th of each month).
I've worked for my school for 8 months, and am already looking at renewing my contract for another year. I enjoy the hell out of my work, and while I've had problems with my school they are all minor ones. You will run into problems working anywhere, that's just the nature of working any job, but you can easily get anything sorted out as long as you are level headed about it.
From what I hear EPIK is pretty sweet though. It all depends on what you want to do. If you want to work with kids you can go through EPIK or hagwons, but if you want to work with adults I think you are pretty much stuck with hagwons unless you want to take a shot at working in a uni. I'd be more than happy to help you with anything you may want to know about hagwons. I currently work for YBM ECC, so I teach kindergarten through 5th grade (with a focus on kindergarten). I can answer most knowledgably on the topic of elementart level hagwons, but I can at least give you what I've heard on anything else.
And really, like matthew254 said "the fewer surprises the better". If you narrow down your choices always ask to talk to someone at the school you are going to work for. If you are going with a hagwon there will always be at least one other foreign teacher there, try to get their email address. They will always be honest with you, and can even try to help you get set up!
Hope this helps at least a little! Good luck!