Yes I've used them twice and been quite impressed. It picked up a vitamin D and an iron deficiency so I've been able to correct those
It flagged up a CRP level of about 13 with notes telling me this was 'highly abnormal' and I MUST see my GP immediately saying it was an inflammatory marker that could mean I was at high risk of a heart attack or something else hideous.
I panicked. Managed to get a phone appointment with my doctor who was most perturbed at my panicky ramblings. Told me the result was within the norm and nothing that would worry him in the slightest. And - crucially - told me that doing these blood tests without a clinical reason meant that they'd flag stuff up that could be incorrectly interpreted.
So I'm on the fence. I think they're good for vitamin D, B etc ... and your first test is relatively cheap as you get decent discounts. I wouldn't rule out doing it again as thanks to doing it I now have corrected some deficiencies