I've tried both, and would say stick with the Magnum XLs for girth. The Maxpros were indeed the same size as the Mag XLs, but I actually had a much harder time getting them on. They were fairly comfy once they were on, though.
I also had a reaction to the lubricant that sent me to the doctor two days later, but I'm sure that's just an individual thing - your results may vary!