PRO model for sure
I bought my wife a new 2012 600 PRO 155 last year. My reasoning was pretty simple, I wanted to get her the lightest sled possible that will help her progress her riding skills. I figured the lighter it is, the less power she will have to use to side hill and boondock. Which means she will have better endurance throughout the day by using the lighter sled. Which hopefully, if I'm lucky, she has just enough endurance to last in the bedroom. hahaha. Go with the PRO!!
Oh yeah, my wife is 5'7" and 115 and can handle the pro with ease.