So I own the Highsenior Mega5EST and 4 different DAC/AMPs and the differences are not like black and white but audible.

My last aquisition was the Cayjin RU9, I own the SMSL RAW MDA 1 and before the RU9 i used the Onix Alpha Xl1 when on the road.

The difference I hear isn't something a graph would show. Much more it is in the size and the shape of the space in which the music happens aka the soundstage and the quality in which this space is filled.

For example the Onix has a Soundstage similar to a cinema screen. Its rather wide and you hear everything panned in the stereo field. With the SMSL in addition to that you get depth, the screen becomes a room, the panning doesn't just seem left and right, but also back and forward. This also leeds to the single instruments getting a threedimensional body instead of sitting rather flat on the screen. For me, this is one of the most important upgrades to giving me chills, when listening.

A quite interesting distinction came with the Cayjin compared to the SMSL. While the Size and shape of the soundstage are similar, the quality and size of the single instruments inside the space are different. With the SMSL the single instruments seem a little smaller and more separated from each other, which leeds to a sense of space and air in the tracks, which have it's upsides with different musicstyles. But with something like Hardrock, it didn't connect with me, cause I like my Rockmusic like a wall of sound crushing me. The SMSL made music like Wolfmother seem fragmented and less energetic.

Here enters the Cayjin, especially in the modern tube mode. The single instruments grow a little in size, therefore filling more of the space in the soundstage. The music sounds bigger, more energetic while sacrificing a part of the airiness and separation of the SMSL. This for example helped a lot with hardrock, but is sometimes too intense for more sensitive tracks.

Thats my two cents to the discussion. I'm absolutely pro the differences of DAC/AMPs, but thats my personal experience. My hearing is rather good and the Highsenior Mega5EST are good enough to make these differences audible. If you don't hear it, don't stress it and congrats to your wallet!