For portable because of the battery the d is good, maybe for critical listening the others are, remember their all good, but the d is for on the move specially in the big apple, I love my x5, and j haven't received my xduoox3, and to have a collection I'm thinking ak120 2, one of the ibassos, dx series, but now I can't see myself on the go with big stuff, unless I'm going to the park, and I can take my phone , note 3 with the 18k kunlun awesome combo, sounds incredible, plus wifi, but I also have my note 8.0 and 10, but the ten is too big , now the 8 is perfect with its case, battery, and a nice amp dac , doesn't really needed they come with a wolfson ,let people know, I wanna get the flc8s, I heard it's great and I wanted the lza2, but I had it and I think my brother took it to dominican republic, dqsm is nice I heard but I already have the sony xba a3, so that's the reason I want the fl8cs it has 36 configurations, after that I will stop buying stuff until next year, and then it's time to download music and movies and enjoy all this equipment and we have no time to do critical and enjoyable listening, I'll back off a little from the sites you have to make freaking time,mother wise whats the use.lol, I'll keep you guys posted ,I love this site, I heard the macaw rt10 is really nice not like the macaw gt100s, but close with more thundering basssssssssssssss, yeah jh budddyyy, love music ,all type.