I loved the M3X (still do), great size/sound and extremely portable so the M6U was the next step up being slightly bigger but still portable. The M6U is another great sounding Shanling player, I stream music via Tidal, Amazon, Spotify and play directly off the SD card. I have used Musicteck a couple of times now when I have needed to upgrade my equipment and I have found them to be price competitive and very speedy with delivery. All in all I have been very happy with my purchase.