I've stayed at the Anaheim Marriott quite a few times over the years even dating back to high school when I was here for a Key Club International convention in the 1970's. It is a great hotel for conventions and a very good hotel for families heading to Disneyland when there are not conventions on.
I say for families when there are not conventions on, because you can get great rates and the hotel tends to be quiet. When there is a major convention going on, it is just too busy.
Nice onsite restaurants, a decent pool area and a well trained staff are all pluses here.