Best mid handheld for Wii u

So I'm looking at upgrading to the retroid 5 from the rg40xxv. I mostly want to play platformers like some of the later Mario's and although the rg can play ds, the split screen fit makes it too small. With the rp4p only being slightly cheaper than the 5 is there any alternatives around the same price? Also any game suggestions for games like Mario, inside, illuminate(?)