We have stayed at both and both have their own perks and charm.
The CR *is* very family-friendly, IMO. First of all, it is a short walk to the MK in the morning and the first monorail stop at night. Super convenient! Having to simply ride the elevator down to catch the monorail rules! My kids love the arcade and also the pool, even though it's not "pretty" like the Poly's volcano pool.
The Poly is really attractive and if you like "tropical" then it's the place for you. My younger daughter loves the beach and the boat launch to the MK... she also liked the CR but asked if we could "go back" to the Poly next trip.

As others have noted, transportation is great here, too, but if you are a Magic Kingdom family then CR edges out the Poly. I prefer the restaurants at the Poly. The downside, IMO, is that the monorail can be crowded in the morning and some longhouses are a good walk to the GCH.
Try one and next trip, try the other!

We stayed at the CR in October and it was great. I had stayed there during WDW's first year (I was 3) and wanted to get my kids there at least once (it took some "convincing" for my husband, who never liked the looks of the CR. Well, my husband is now a big CR fan). Next trip, because it's beautiful and because my middle kid begged, we're going back to the Poly after a few days at the AKL (I've wanted to try it for years).
Best of luck with your decision!