We recently (February) stayed one night at each. The point values were the same for us so we decided to try them both to see where we wanted to go back to. The pool at the Hilton was GREAT for DS (2.5). The lazy river was really nice. But, you can use it even if you are staying at the Waldorf.
I don't have an equal comparison because we were upgraded to a one bedroom suite, fireworks view at the Waldorf and had a standard fireworks view room at the Hilton.
Service at the Waldorf was better (they wouldn't let us make up our own sofa bed and scheduled it to be made up while we were out at dinner - came back and voila! it was done) but I felt a little more comfortable at the Hilton.
We were kept waiting for at least an hour for our room to be ready and I got pretty nervous trying to occupy my 2.5 year old in the beautiful lobby in the Waldorf, whereas the lobby of the Hilton was always bustling with kids and activity, so it was just more "family friendly." With your princesses, that shouldn't be an issue and they might really like feeling like the princesses they are at the Waldorf!
Either are a great choice, we enjoyed both very much.