Go to a reputable nursery in your area, ask the oldest guy who works there about it.
You want to choose something that will work in your climate zone, first off, then it is bare root vs something in a container. I believe the consensus would be bare root, if you spoke to knowledgeable people about it.
When I was picking out peach trees, I got an early and a late one, same as the nectarine. This will give me fruit for a longer time in the summer, so I can brag about it to my family and friends in Texas, Nebraska and points harsher, maybe even overnight them some so they can really appreciate why it is not just the humidity that makes Californy the place you ought to be in the summer.
You can do the same thing with apples, some are self fruitful, some need pollinators, you can get green ones, stripey ones, what sort of apples do you prefer? I like white nectarines, but they don't travel well, so I have one out back. I swear I have been thinking about putting a couple trees in the back instead of a lawn. A few bucks up front and some copper spray a few times a year to keep the curls and blights from wreaking too much havoc and you get fresh fruit for life. That copper stuff keeps the black spots off your rose bushes too.
I have seen those multiple graft trees not work out very well for a few people, on cherry trees and apple. That may have been user dependant failure though, not surprising considering the individuals raising the trees.