I just went through the same ordeal with my wife. Fought with her the longest time to get a decent mountain bike before hurt herself. We had her try out various women model bikes and men modeled bikes to see which she felt the most comfortable on. She liked the specialized rockhopper disc comp alot, however, she chose a Gary Fisher piranha in the end. She said the bike felt good under her, handled and turned very well, and liked the component setup (sram 5s and hydralic disc and Tora 302).
If i was you, and had 700 to spend, i would look at the piranha over the marlin with disc. If she doesnt like then you lost maybe 5 minutes. But i was shocked how quickly my wife warmed up to that bike. Now she is beaming ear to ear about her new mountain bike. Actually a good feeling for me too. Take a look at the piranha...she seemed to like it alot better than the Marlin she tested.
Oh yea the piranha come in at $700.