1 Up, 5 Down (GP) Shift Pro's and Cons?

Hey I'm thinking of changing the shift pattern on my bike to 1 Up 5Down...
I'm trying to think of any negatives of doing so, so far the only thing I've come up with is if I ever let someone else ride the bike they'll mash through the gears getting used to it. But no-ones ridden the bike in 9 months so I doubt that's going to happen.
So, pro's and cons?
Cheers
I'm trying to think of any negatives of doing so, so far the only thing I've come up with is if I ever let someone else ride the bike they'll mash through the gears getting used to it. But no-ones ridden the bike in 9 months so I doubt that's going to happen.
So, pro's and cons?
Cheers