What App are you using for your USB DAC?

For those of you using a USB dac I am curious to know what iphone/Ipad apps you are using to control the music from your listening chair.

Please list pros and cons

(assuming you are using a PC/MAC as the source)

I'd love to know if there are other options that would better its functionality.
For my main rig, which runs JRiver inside the computer, I use JRemote on the iPad and also on my Android phone. Just excellent, in my view.

For my travel I carry my phone and an iFi nano DAC. The phone connect to the nano thru USB and I use USB Audio Player Pro as the app to stream audio though the phone USB. It's ok. Not great, not bad. It's a bit quirky initializing the DAC at times, but sounds good.
- interfaces with iTunes nicely
- works on droid tablet or phone
- provides similar views/sorting of songs as iTunes on both devices

I also use Audirvana on the iMac to bypass iTunes playback control/code