The Shortcut is an excellent unit, and when operated right can handle most hill applications with ease.
One advantage of the shortcut is it has a commercial duty hydraulic drive system, the FasTrak has a drive system made for the homeowner.
Either unit should handle your hills with ease.
The Mini Z will be coming in the near future, it will have more engine options than the FasTrak and a commercial drive system.
It will also have larger tires, better seats, and easier accesible areas than the FasTrak.
The Mini Z will be available in 19, 23 and 25hp Kawasakis and 20 and 24hp Hondas with 44 and 52 inch cut
There will be the standard Mini Z and the Super Mini Z.
The Mini Z and Super Mini Z will be the industry leaders in small frame ZTR's
Hope this helps