Can't say anything about the M1 but I have the V-dac MKII. Best thing you can buy for it's money in my opinion. The soundquality is amazing for such an inexpensive price. It has tons of musicality combined with a lot of control. But ofcourse it has its limits, in my humble opinion the biggest one is that with a lot of HQ-files I lack a natural flow, somewhat to digital, most noticeable with voices. But other then that it is terrific.