I think it will be hit or miss. It depends on who actually comes and does the work as they sub-contract the work out (unless you're in the Salt Lake City area as I've heard they have company employees doing work in their home area but I'm not sure about that).
They have a weird franchisee/referral program so in most, if not all, cases you are not actually getting a company employee but are referred to a local detailer in the area you desire the service. It's almost like a referral service and you are paying for that middle-man to take care of that referral. At least that's the way I understand it.
I think you'd do better by researching a good local service on your own by scrutinizing Google or Yelp reviews and not paying a third party.
Even though they have an A+ BBB rating, they seem to have an inordinate number of complaints on file:
Complaints -- National Detail Pros, Inc.
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