I've done 23 & Me and then my sister's family and my parents have done Ancestry DNA. I was more interested in the DNA health information so that's why I picked 23 & Me, though I think Ancestry may have added some of this stuff to their report as well since I did it. It is interesting stuff, but I think it's overpriced for what it is. My DNA provided some interesting tidbits, but produced no known health risks...which is great but also makes the extra cost feel like a waste of money lol. The geographical origins stuff was more interesting than I was expecting. If you've got some money to blow and are curious, then go for it but don't expect to get anything tangible from it and you may just set it all aside the day after you get the report and never look at it again. The anticipation of getting the results is greater than anything after having the results, imo.
If you have mysteries in your family history though, it could be very useful. A friend of mine, whose father was adopted as a newborn, did one of the tests(I think Ancestry) and was actually able to find his biological grandparents.