We stop in Yuma in December each winter before we head to southern California, we found a nice lot rental in the foothills close to the desert (good neighbours and $300/month all services included) The Christmas lights and parade in the foothills is nice. Last winter we stopped for a couple of days at a RV park on the way back through in late February/early March, we found Yuma at that time to be too busy for our liking, heavy traffic and busy stores.
What you decide depends on your wants/needs.