First off, read the trail riding vs XC riding thread. Will answer that question. Short answer, nothing.

Personaly, I'd go with the Kona. Slightly better components. IMO and many others, buying better quality used it better than buying lower quality new. And if MTB turns out to not be your thing, you only spent 900, not 1500. Is the kona at your LBS too? If it is, go ride it. You'll probably like it. Kona's are nicely made bikes. MAKE SURE IF FITS!!! Have the guys at the shop give you a hand if you need it. If you do go with the Kona, then you have the extra money to get things like helmet, gloves, hydropack and whatnot. Maybe better pedals and shoes if you want.

But again, make sure either one fits. The best bike will only turn out to be the worst if it doesn't feel right. And then you won't ride it, or spend a crap load more time and money swapping stems, bars and all that jazz, only to still have a bike that doesn't fit. Fit is very subjective at times, thats why I say ride em if you can. Maybe the shop will let you take it out to some trails. A spin the parking lot or around the block can't tell you jack.

Being a chick doesn't matter. well, maybe when it comes to saddle it does, but nothing else really.