VO2 Max Testing - worthwhile?

Depends on how much of a data head you are.  Do you need to know your VO2max to train effectively...no.  It's just one more peice of information that can help to guide you.  For me it was worth it because I was curious and I also got some other information out of the test like my LT, aerobic threshold, pace at threshold, velocity at VO2max (which helps to estimate race pace and training paces). 

Well worth the money if you are going to be disciplined enough to use the information once you get it. If you are not going to put the information you get to good use then I probably would not waste my money.