Visit the FiiO site for a full breakdown of all its features.
I would prefer to leave it without the case, as I would also like to with other daps I have at hand - but protection against bumping and accidental drops are paramount. So I keep it on (leather case).
The FiiO X7 Mark 2 fits nicely within the palm of ones hand, the weight is similar to other daps of this size. It feels solid in its build.
The RK3188 CPU and 2GB RAM, as compared to the X7 1 GB certainly shows in the speed of the UI and experience of the daps touchscreen. Very fast and fluid.
The DAC ESS9028 PRO certainly is an improvement over the ES9018S Dac of the X7 and is also a DAC chip that many other dap makers of late seem to be turning to and using also. It certainly takes care of any of the past Sabre glare issues.
Dac functionality isn`t completely functional as of this writing, although some users on Head-fi have found a safe work around.
I was in two minds about its sound as I routinely switched from Opus#2, Alien+, Opus#3 and the DX200 during the listening portion of the review process. Some days I would carry 3 daps and 6 earphones with me on my daily commute just so I confirm what I thought I was hearing as I was in the depths of a three way dap review. Those being the Opus#2, Alien+ and the FiiO X7 Mark 2, each being stellar in it own realm but each bringing a little something different to the table.
I found the FiiO X7 Mark 2 on its earlier Firmwares to be fairly neutral, transparent, detailed and with decent separation, but with a slight twinge in the upper reaches. Maybe a result of DAC choice, firmware or going to the other extreme from the earlier FiiO warmish in house signature sound.
later when I updated to the more recent Firmware of late September 2017 I noticed the highs had been tamed somewhat, or the over all body had been bought up to match. It definitely seemed to have the appearance of more power after the update, before it sounded a little bit thin and lacked a certain beefiness.
The X7 Mark 2 is generally neutral, linear and seems to handle the highs well. It departs from the earlier darker sound of earlier FiiO daps perhaps partly in a change of Dacs from AK to ES/ESS and by way of intentional design.
Resolution and separation are great, but not excellent in comparison to daps at a higher price point. Though this is to expected. Although it does pack plenty of detail and dynamic range it offers an enjoyable musical experience whilst staying true to the recording.