The pool at the Embassy Suites North is indoors and kept at a nice temperature for kids. When we were there it was almost bath water temperature. The hot tub was also indoors and kept toasty. (Can water be toasty, it would seem that toast in water would simply be soggy?) Since we are usually there in "winter" we enjoyed having an indoor pool. My kids like to swim, and I am usually the designated "watcher." We have stayed there when the sunny California was doing a great impersonation of Seattle, and it was nice after a drizzle day in the parks to be surrounded by the lush tropical plant, having a "grown up drink" while the kids played in the pool.
If you want to work on your tan at the pool then the southern hotel would be a better choice for your family.
THe Embassy Suites South is newer, larger, and a bit more upscale as far as decorations and elevator design. I found their re-done rooms to be as nice as the North hotel and they had a bit more storage for stuff in the closet area, but the bathroom wasn't as nice. Simple tile and countertops, nothing to "write home about." The pull out bed in both places is better suited to kids than adults. If your kids are small enough, you can have them sleep "across" the pull out bed and avoid the bar that will poke them in the back otherwise.
The Northern Embassy Suites has a more Spanish feel to its architecture while the Southern Embassy Suites is much more modern and has cleaner lines and feels quite a bit more sophisticated.
We really enjoyed that the breakfast service, at the Embassy North, was in a restaurant area, and not just out in the lobby. It was much quieter, in comparison to the open lobby at the ESS. As to evening snacks there are plenty of "kid" options. Each place offers kids soda, or kid friendly mock-tails like a Shirley Temple. When we were at the South hotel they had pop corn one night, a sort of trail mix another night, and pretzels. They had pizza for $1 a slice. At the North Embassy suites they had a veggie platter as well as salty junk food.
The one place where the South Embassy Suites totally blows the North out of the water is their restaurant. The restaurant at the North Embassy Suites, not the breakfast provider, was overpriced and bland. A total waste of money. The Restaurant at the Embassy Suites South served much better food and had better service.
--Eeyore's Wife