Remember this is all measurements based only, the sound is what matters most and isn't always related to what a measurement says unless it's all over the place on which case inference can be made easily. So yeah as we have already found, what headphones you have will dictate what the sound is like, either lacking in upper end detail and sounding mushy, or sounding great.
For me it didn't meet my expectations for sound or polished software experience, but it was cheap so there is that.
I found the K11 R2R to sound better with Hifiman for comparison, no loss in upper end clarity and a wider soundstage so the K13 R2R must be even better going by what people heard at CanJam and that should cost around the same as the DX5 2's RRP so I don't see any reason to bother with the DX unless space is a big issue.