I found it pretty useful too. It didn't pick up a couple things I react to by swelling for a day or two, but it picked up things that cause me to swell for a few hours. So maybe some different mechanisms going on in my reactions to foods, and the test only picked up one kind.
But it did seem pretty accurate - it caught cranberries, sesame, and soy, also bananas which I knew about before (and had the shorter-term reaction to). It listed pretty much all dairy, especially casein but I don't seem to have much reaction to that - so I'm not sure if I really react strongly to whey, or that just got picked up because I'd been eating a ton of casein protein drinks.
Either way, it's good info to have, especially if you're reacting to a lot of things and having trouble figuring out where to start. Then you can eliminate all of those things and see if GI/immune symptoms improve, and see if you need to try a more restrictive elimination diet for a bit.