It's a tricky one really. I've had a funny relationship with the M11 Pro before and now this is similar - on one hand I get annoyed that it's flatter than Keira Knightley, but then coming from other more grainy source (ZX507 and especially N3Pro) I appreciate it's cleanliness and technicalities.
For practical travel purposes I find my ZX507 and IERM7 a more holistic pleasant experience overall - nice enough sound quality, global eq, streaming and gplay, very small and portable.
But then the M11 Plus is something different - it gives a very technical performance similar to a high quality desktop DAC, has the technicalities wow factor but also brings it's own can of worms as just being a bit too "technical" and not offering an organic flavour.. it might be just the AKM dacs - if I'm honest I've never been blown away by them in all the different sources I've tried... earlier versions are grainy, and newer ones seem to go for a Japanese/Chinese definition of HiFi that exaggerate certain audiophile traites: the bass is super tight and agile ( - too tight, needs a little bloom and natural decay warmth), mids are clean smooth but with a touch of echo to create that feel of distance (but as a result sound a little DSP'd and not exactly natural, they should be just as is ideally), and the highs are sparkly (- a little too sparkly creating that feeling of uber resolution, but in the process not allowing some darkness and natural dampening to come into play to create a sense of calmness).. that's just my view.. I do find that Sabre chips when implemented well can offer a more natural sound; Apogee Element being the best implementation I've heard to date (easily competing with Chord Qutest and in some ways more natural) - it's a sabre chip, i.e. very neutral, but somehow still offers feeling of inner warmth and calmness... the Fiio doesn't quite reach there.
Sony ZX507 is at least a Sony - they make an effort to make some cohesion and naturalness in their sound with their own s master chips, even if it doesn't measure amazingly well, and can appear less technically proficient, it can be a better fit for some.
I haven't heard the iBasso DX300 but reports that it sounds organic has me intrigued.