Hopefully it beats Toyota certified.  We bought a "certified" Tacoma from a major dealer and straight off the lot it needed a new radio and a week later two new catalytic converters.  When we were arguing over who pays and how this 100 point certification never included things like turning on the radio they took me in a back room and admitted they buy these vehicles at auctions from lenders and just wash them and put them up for sale.  They really depend on the low milage and the quality of the build of the vehicle to turn the profit. It may be different now but then there was no actual standard as to what "certified" means and it's all marketing. 
That said, a truck with 20k is a lease return, most likely had all its maintenance done at a dealer on schedule and is a safe buy.