I signed up because I had studied genomic medicine a bit (pdf), had read Kurzweil's advice about taking advantage of new technologies, and there was a discount!

It's quite a bit of fun to browse, and I've learned a few things that might be useful. I'm a carrier for PKU, which will make me extra vigilant when/if I have children (plus make me encourage my wife to get profiled). Also, gwern pointed me to research on a gene-drug interaction for Modafinil, which indicates that I am not likely to benefit from the drug. Lastly, my grandfather died from Alzheimer's, and it is my absolute most dreaded diagnosis. Finding out that I'm at a substantially decreased risk (Relative Risk=0.69) for the disease was a surprisingly large relief.

PKU is part of prenatal screening in Canada, and I'm not sure how much confidence to put in the Modafinil or Alzheimer's result. It could thus be argued that these examples are of limited benefit, however coupled with the pleasure I've gotten from browsing my genome and the potential for further developments I would say that it is worth the cost.

If you can wait until April, they've had a steep discount around DNA day each of the past few years.