I would suggest shadowing both practitionaers in many different settings before you decide...thats what I did.
Personally, I dont think I would have been happy as a PA. I would always want to take the extra step and would not necessarily be able to do that without a medical degree.
I think much of it also depends on where you are starting from...age, prior medical experience, other responsibilities, etc.
It is difficult for 40+ year old people with kids, a mortgage, etc to pick up and start medical school. I see it in my class and I am hella proud of those people, but I also see the same situation in the PA students on campus and they have a much easier time with that sort of adjustment.