Not trying to derail the thread but as I have Alien and Walnut I would like to chime in;
The RMAA response - we are measuring the FR out of the PO, not what is actually coming out of the phone. I have been using with Monk+ as my budget portable and really enjoying it and below is an RTA of the FR coming out of the ear bud post some minor EQ via FB2K
Call it synergy but I'm just not missing much. Perhaps I'm not as concerned with infrasub freqs as I listen to Cohen, Bowie etc but Daft Punk sounds fine too.
Do I like Alien, sure I do but defaulting volume and memory location can be tiresome. I feel Alien has a wider sound stage and better resolution.
Do I like Walnut, sure I do. The sound stage is more narrow but still okay, call it engaging, and the dynamics are great! Not too mention it resumes at the exact moment you turned it off which is awesome and makes Walnut a clear winner in my book. So I have to adjust EQ slightly to make it right for my ears/preferences, no biggie. I try to be a purist but other sound systems get EQed and no one cares as long as you are not sacrificing FR or Dynamic range.
Being able to adjust digital volume to vary range of the analog volume is also nice. I was listening a pretty low volume yesterday and had a nice range of motion via the pot.
Weight - it's light weight to the point that my earbuds almost pulled it off my desk the other day. Easily pocketable without issue. The C3 is heavy IMO.
I would recommend Walnut just for the fun of it! It has an enjoyable signature.
Back to Alien...