I got the xduoo x20 for few days now but because i'm not really experience with DAP so i'll just share some of my thoughts. First of all interface is really smooth. Totally no lag even when i play .cue files or dsd files there just isn't significant lag or cut unlike the M1s (aune) which i've been using. Gapless works just fine. Secondly, the xduoo x20 is equally if not more powerful than the m1s although i don't find the difference between both the single ended and balanced output to be vastly different. On m1s it is quite the case where i find balance to be more powerful to drive my iem to same volume level as compared to its normal output (about 10 clicks or more) whereas on x20 it seems to be not much different at all with just 1 or 2 clicks max of volume between balanced and normal output (both on high gain) At the moment still don't find the balance output to be very significantly different in sound quality than normal 3.5mm output. Thirdly sound quality wise, i was quite surprised that despite both housing the same DAC chip, their sound can be vastly different. The xduoo sounds more on the warm and inviting side that's very musical and gives a very immersive listening whereas m1s has a much more transparent and dark background which i find to present music much more accurately without added colours. Tho it's just early impression but i'd definitely give a plus in SQ for m1s than x20 but i can see myself enjoying x20 from time to time probably more often too because it just makes music more magical and enjoyable. Not to mention it has almost all the function that makes it much more portable especially the bluetooth aptx and hiby link. Before going to fourth, it's just my personal experience but with same iem (some diy custom BA iem from taobao), same cable, x20 tends to present some sibilance and being more sharp on certain tracks whereas m1s doesn't. Not very significant but notable. Probably just an isolated ones on this particular iem. Haven't got the time to try with other iems coz it's a busy start of year, barely have any real time. 4th point. Built and quality. X20 appears to be more better in external built. More compact if not slightly heavier on the x20. All the buttons are firmly embedded whereas on m1s there's some looseness in buttons especially when you shake the device, you can hear it. However, there's something very significant on the x20, there's this faint constant background clicking sound during playback of music and it'll cut sometime after the end of playback or during long pause. I've read somewhere that it's the relay sound of the circuitry and it's supposed to be normal but i'm not too sure about it since m1s doesn't have that so in circuit design i guess aune did a much better job. Lastly, i really can't unzip the firmware files downloaded from xduoo site. Not sure why maybe it's OS problem or what i dunno. Curious to know what the firmware 1.1 changes, anything significant ? That's about all i can share. Hope it's helpful coz it's my first time writing about DAPs, i don't really play with DAPs a lot. My personal take is x20 when i wanna enjoy music, more fun and casual, on-the-go. M1s when i wanna do some serious listening, for A/B comparison of iem.