I've been using Forte Ensemble and have been very happy with it.
I spent a long time looking at as many others as I could find and I went with Forte because it had a very nice look, is very easy to use and has a lot of nice features.
Forte is designed for live performance also so, one of the great features is that you can save a "rack" which consists of instruments and all settings and routings for the instruments and then when you load that rack it is setup exactly the way you want it.
Midi and audio routings are very configurable and are saved with the rack.
You can save as many racks as you like. A rack is a file that is saved to your hard drive, so they can be back up also.