I go every year and over the past two years the actual technical information has declined. Mercury is pushing hard on the BTO solutions and neglecting the testing tools. Overall the experience is worth it though. Just the networking alone is a valuable asset. Meeting others with similar interests and experiences. I personally think the pre-conference training days are excellent, if you can afford them.
If you go, try to get there Sunday night for the reception. It is really a lot of fun.