I had it done... luckily I only spent a few hundred on it. I actually felt really good for a while. However, all my allergies eventually came back. You have to fix the root causes that are causing the allergies: leaky gut, parasites, bacteria, yeast, imbalances, defiencies, emotional, interference fields, etc. One of the best people I have seen for getting at these root causes is Dr. Bob Marshall.
His website is http://www.healthlines.cc
He has a radio show so you maybe you will have it in your area.
NAET is an interesting technique, but probably doesn't strike at the root cause for most people, especially adults. For children, however, I hear that it has fantastic results.