I recently bought a TT2 and M Scaler, which replaced a DAVE and Blu 2 which I owned for a year.
There is an issue I have with the M Scaler, and which I also had with the Blu 2.
The results I get with the M Scaler and, previously, the Blu 2 are both positive and negative. With the M Scaler engaged, there is what seems to be a massive drop in the noise floor of the recording. Low level detail which was previously masked is now more obvious. Timing of transients is sharper and more defined. However, with upsampling engaged, there is also a loss of fullness of sound; there is a new leanness, a lack of bloom around instruments. With the M Scaler, I can hear to the back of the hall, but nothing in between. At native resolution (with the M Scaler bypassed) I hear the fullness of the room, the sense of space around the instruments. And more importantly, the M Scaler seems to remove tonal colour - instruments seem to sound richer, warmer and more colourful when the M Scaler is bypassed. With upscaling engaged the sound is tonally lighter, cooler and somewhat bleached. It is like a skeletal version of the real thing. I am not convinced that this is merely the removal of distortion.
I am now leaning towards preferring the sound of the TT2 without the M Scaler. There is more body, more colour and more tone, at the expense of some forensic detail. I wonder if anyone else has had a similar experience.