I'll throw this out there: I've had better luck with my hybrid Bluegill than I have with hybrid (dwarf) fruit trees.
Part of the problem lies with me. Our dwarf trees sometimes produce sooo much fruit that they become heavy, and we've had two blow over, roots and all. That might not have happened had I thinned the fruit like I should have. Still, they appear to me to be shallower rooted than our full size trees, possibly due to the planting requirements required of hybrids.
If you decide on a hybrid tree, they will tell you to be sure to keep the graft union above ground level when planting, so you don't lose the benefit of the grafted on rootstock. The tree can sprout another set of roots at the union, rendering the hybrid rootstock useless.
