I balked at the price of the Pono, but I'm very happy with my FiiO X1 for $100. JRiver Media Center made it so easy to convert and transfer files. I don't use a portable often, but it also sounds good plugged into my old Bose Music System the the CD quit working on.
The only downside is the Fiio puts all the tracks in alphabetical order. I added track numbers to the filenames in JRiver when I converted all the apes to flacs on concept albums, live concerts, and classical to preserve the continuity. I doubt anything but JRiver could have got me through it.
The Fiio community forum is useful for telling what the device can't do. Thanks J River for the "can do". This question is moot now, but if I had converted my 96khz 24 bit files from flac to ape, would I have lost any sound quality? I probably wasted a lot of time converting the 44khz 16bit files to flac. The device will switch formats, but you get optimal speed and battery power if it doesn't have to.