I like #4 best. #1 is to small, #2 Looks weird to my eyes, #3 the R an M kind of hard to see the letter looks like a black blob, #5 is a little scrunched together. Dang I am picky. Maybe I should get my eyes checked.
I like the all caps for sure. Based on what this is for, I would say 3 or 4. It will be easier for people to see from a distance I would give the edge to 3.