EX has been very durable for me, easy 5-6 months. UPP was going strong at 4 months when I rewaxed a customer's vehicle. #16 on a white Expidition is still beading and looking great at nearly 4 months now...and we had a ton of rain in November. CMW has been pretty durable too, 4-5 months on most vehicles, even more on those washed exclusively with QEW.
On a dark metallic, UPP and #16 would look best. Dark solid colors, CMW and EX, if that helps you make up your mind.