I worked briefly as a level designer myself. I don't know if it was the particulars of my own situation or the industry itself, however I left my job pretty damn jaded. I worked at a small company in Middle of Nowhere,USA, growing up as a city kid that was probably the biggest change to adjust to. Our project was essentially a Quake3 imitation to be released 3 years after Quake3 using inferior technology. That didn't really bother me, I knew you would have to go through some difficulties to get a decent job in the industry in someplace you like to live. What did bother me was our engine creators. These people basically had no respect for people doing art/content related stuff. Our level design tools were complete and utter shit. Before I took the job I asked the project lead if the tools were going to be improved, he said yes we will take your feedback, we understand they need to be improved. Once I actually spent a lot of money relocating and basically turning my life upside down to join the project, that answer turned 180degrees into 'the tools are not a priority'. After struggling to try to make decent looking levels, I just said 'fuck this builshit' and quit after a few months.

Things that influenced me into this decision. I couldn't make decent levels at work, and doing more level design in my spare time was the last thing I wanted to do after mapping for 60 hours a week, then how I am going to get a better job? I really couldn't stomach the possibility of making only $30k to $60k a year for the rest of my life, the job I was working at was under $20k a year, living expenses were non-existant in that back-water shithole town. Job security was a big concern, I felt very expendable as a level designer in a volatile industry. Just look at what happened today to all the great talent working on Elite Force II, project done, layed off. It's really unfortunate, I wish them the best of luck landing on their feet. All these factors led me back to school for a Computer Science degree. $100/hr doing consulting work? Wow suddenly corporate bullshit doesn't look so bad.

I've had a few run-ins with the game industry since this time. I interviewed at Blizzard, and also was offered a position with an EA subsidiary. I didn't get Blizzard and turned down the EA position. I would of loved to work at Blizzard, but oh well. Overall level design is much more gratifying to me as a hobby. I had infinitely more fun polishing my level design skills to a professional level in my spare time, than doing the job full time. I think I'm going to keep it that way, unless that true dream job comes knocking. 

I've just started a job at a developer and Im finding it really great. Everyone is friendly, the tools are good and most days I dont really notice that ive worked overtime.

Sorry to hear that its not this way for everyone :( It *IS* different from what I thought it would be, but this hasn't affected my love of the work, you just have to go into so much depth and detail in the industry whereas in your own projects you can throw stuff around and chop and change it whenever you like.

All in all its been well worth it for me, and worth all the risks that come with it imo.