Positive Grid will be releasing Bias tomorrow. This customizable amp modeling app has got guitarist rightfully excited. It is a lot of fun to dive into it and tweak up your own amp for use in JamUp or standalone.
Synth nerds should also give this some consideration! I've been playing with it a lot lately and getting some nice warm crunchy sounds out of both analog synths and synth apps. You have so much control over every aspect of the sound that I think synthesists will love it.
Rather than run it through the full JamUp guitar suite of effects, I've been chaining Bias in Audiobus to go through Turnado and Echopad to great effect!
Several folks pointed out in my Volca Bass video that the Volca sounded best when run through the Sunsine Audio Vanishing Point distortion pedal. I agree, and was unsatisfied with the distortion on Korg's own Mini KP2, but had a hard time justifying buying a second Vanishing Point. So I connected the Volca Bass to my iPad with a Rocksmith cable, and set about crafting my own custom tone in Bias!
Here is an example of the amp I created with the Volca Bass! I switch Bias on and off throughout the demo, and have annotated with SoundCloud comments to indicate what I'm doing.