My main thought is that these are 2 totally different bikes. One is a 27.5 and the other is a 29'er. When you go downhill and make turns, which feels more comfortable. Even though the Trek is not out yet, you really should demo a 27.5 vs. a 29er going uphills and downhills, not in a flat parking lot. They should feel different.
If you still cannot decide and both of them "feel the same" to you, then I would pick based on color.
2014 Liv Lust
2013 Specialized Fate Expert with carbon wheelset (sold)
2012 Specialized Amira Elite
2010 Santa Cruz Juliana with R kit and Crampon pedals (sold)
2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle (sold)