These types of events have pretty much turned into scams.
What used to be a really cheap and easy way to get visable, make contacts and generate interest in your products and services has turned into an expensive venture that takes a serious marketing approach just to break even.
It can and does work for some, but often it's because "there's a sucker born every day." It depends a lot on your product/service, the venue, the market, your approach, and luck.
Thinking it through and knowing what you are getting into is important and, without quite a bit of experience, difficult.
On the other hand, if thee up front fees are not burdensome, and you go into it with a reasonable set of expectations and an open mind, these events can be fun and provide good opportunities. It's just that the odds of that experience being profitable or very positive are decreasing... in our experience.

