I have not compared Enqueue, just Amara and Fidelia to the AUDIRVANA PLUS 1.46 and more recently Beta 220.127.116.11 (sounds great!).
One thing is I deactivated itunes completely in the settings and just play my HD flac files.
I found that AUDIRVANA PLUS improved my HDVD800 nicely, more air, more soundstage and a little more detail. You can also use a custom settings to up-sample your music files from 44.1kHz upto 192kHz without a DAC. However I still prefer the standard settings.
Have a listen, for a few days and play around with it with HDVD800. Hope you gentlemen enjoy it as much as I do.
BTW, if and you are using an app that's better, I would really be interested.
Here are ome reviews for your interest.
Audrivana Plus Beta download for who ever is interested.