I have attended several over the years. When the economy is bad it is just a depressing place to be. The last one I attended, I was surprised how many techies were looking for work. Feb 2008, I thought the job market was strong.
Imagine my surprise when I saw my boss there! LOL and she was truely shocke to see me there.
There were only 6 employeer looking for people and must have been 50 people looking for a job. I talked with one company which was MUCH closer to home.
Interview was successful. The job I was leaving then gave me a significant raise (13%), which had they paid me that before I would not have been looking. I had made myself excited about the possible new adventure. The new job asked me how much pay I expected, of course I quoted the new number. Which they offered me 8% above that.
So I took it. Then less than a year later the bums laid me off.
So in the end, in this economy - I would definitely go to job fairs.