Cypress Pointe Grandvillas probably offers more consistently nice rooms than Vistana Resort. All 2BRs would have an inroom jacuzzi tub (not in the Courts section of Vistana, if that matters to you). If you will have a 2BR that sleeps 6, I think the ones at CPG will be nicer. If you will have a 2BR that sleeps 8, the one at Vistana could be nicer or not - depending on where you are assigned a room at Vistana.
Vistana Resort is larger and offers a lot more to do - especially for older kids and teens. If you plan to spend more than one full day enjoying resort activities, Vistana will offer more to fill a couple days. Vistana's 2BRs are never part of a larger lock-off (so quieter). Some of CPG's 2BRs are actually part of a larger 3BR lock-off (may be a little bit noisy if you have very loud neighbors in the smaller lock-off).
Both are very nice places and well-located. If you plan to spend most of your time touring the local sights, it's probably a toss-up.