Not sure I understand your terminology. Are you saying you are testing two different configurations - both using a soft-synth as a MIDI slave within a DAW to different master controllers. One master MIDI controller uses Montage - and this performs well for both latency and being able to access all the features of the soft synth. When using a different MIDI controller (like a Native Instruments, or Alesis, or ...) MIDI controller that has a USB MIDI interface - you see worse performance both in latency and ability to control various parameters of the soft-synth?

If so, it would help to be specific on what the "worse" MIDI master controller is -- as maybe other users have experience with the issue and know of driver or other updates to fix the issue.

All MIDI controllers have a different "spin" on MIDI in terms of MIDI channels supported, zones supported, and controllers - both count and implementation (Sysex vs. CC vs ...). Therefore if you get one MIDI master controller working in a setup - you'll probably need to adjust your configuration when moving to a different MIDI master controller.

One would expect that the MIDI controller and MIDI path would not contribute to latency. I'm not sure where your monitoring is done when hearing the sound output result of the MIDI controller stimulus -- this may be different when using a "dumb" MIDI controller vs. Montage (Montage may be using the audio path to render the soft synth while the MIDI controller may be using your PC sound card -- which may be where the latency is showing up). There may be other factors at play here - your detail is scarce.

This time I tested this I was using the Kontrol MK II
But I have seen this 3 diff times with 3 diff interfaces that use USB MIDI.
Montage was only using midi As I set the keyboard control to OFF.

Now Everybody(manufactures) is Diff. This I understand.
But Straight MIDI USB from a controller. Should work fast and complete. That is what they are suppedly made 4.

Now This Problem only shows in DAW's. Stand Alone apps. Seem to Work just fine.(Like Komplete Kontrol)

What happens to the sound. Well it can only be described . As not complete. The Richness is lost, Dynamic range is not right.

This time I have only tested in Ableton live. As I have some Great Grand piano sounds preset.
I will test some other DAW's.
But I really would not have a clue. Where to start adjusting anything in a daw 4 this.

Dynamic range, taken literally, means that the velocity curve of your MIDI controllers are not matching your playing style. Montage seems better suited and may be superior of being able to tell when you play soft vs. loud. Some MIDI controllers do not output that many values between the values of 0-127. That's a technical limitation or perhaps something you can modify by changing the settings -- but still - a piano manufacturer such as Yamaha pays much more attention to the mechanics of piano playing translating into values of 0-127 than other companies without this legacy.

On Yamaha and attention to piano playing. We definitely agree!!!

Velocity curve settings I will check.
Tomorrow or Sun I will use the MoxF as a midi controller and see what happens. ????

I just find this an anomaly of sorts.

Well
One thing I learned Kontrol is 'It is Not plug and Play'. Like a normal controller. **Hooked up my keylab And it had the same problem. As in the OP
You need to install the. 'Instrument Rack of Komplete Kontrol Into Ableton Live.(Which I had already done.)
Then Use it like a plug. Then put your Soft Synth into it.(This I did not try until after)
Then it works MIDI wise fine.

So as long as the Kontrol is used like a 'Soft Synth Instrument' That You Place Soft Synths into. All is Good. And I get it. NI.

But as the Keylab Still did this. And it is. Plug and Play. This Midi anomaly is still weird.

The Keylab is a good controller. But the keybed is nowhere near sensitive enough to. Drive The Montage or Really rich Velocity Sensitive instruments.
Hence the. Komplete Kontrol Mk II. Which Key Bed wise. Is Sensitive Enough. That and the Studio Logic SL-73 are really the only Controller
choices out there under $1,000