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)
- 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

Thanks for inputs fellows. Wonder if anyone is using a linux based front end??