Good to know I am not alone with my conclusions.

Fighting with Sonar MFX I slowly come to the conclusion it is rubbish... at least for generating purpose (arpegiators and such). Discussions about fundamental problem there was back in 2003-2013, with the (semi-official) statement there will be no changes.
 
So either they replace MIDI processing part with new approach or it will stay frozen, like it stay last 15 years.

azslow3
Fighting with Sonar MFX I slowly come to the conclusion it is rubbish... at least for generating purpose (arpegiators and such). Discussions about fundamental problem there was back in 2003-2013, with the (semi-official) statement there will be no changes.
So either they replace MIDI processing part with new approach or it will stay frozen, like it stay last 15 years.

Thanks for fighting! And sad to know...

I've used midi-only VSTs like Cthulu and Catanya in X3e and in Hopkinton -- both work fine here. Have also used EZKeys and Kontakt in midi-out mode. 

lingyai
I've used midi-only VSTs like Cthulu and Catanya in X3e and in Hopkinton -- both work fine here. Have also used EZKeys and Kontakt in midi-out mode. 

I use these as well but I think we are discussing different beasts.  These are vst instruments that output midi notes. Vst midi plugins can be applied to a midi track in a similar manner to the mfx midi plugins that come with Sonar. 

lingyai
I've used midi-only VSTs like Cthulu and Catanya in X3e and in Hopkinton -- both work fine here. Have also used EZKeys and Kontakt in midi-out mode. 

I don't know, but maybe it works fine with less number of notes or events, but worse with series of controllers or something bigger. Just a guess.

lingyai
I've used midi-only VSTs like Cthulu and Catanya in X3e and in Hopkinton -- both work fine here. Have also used EZKeys and Kontakt in midi-out mode.

Not that I do not trust you... I have tried several plug-ins and to understand my observations have written simplest possible MIDI VSTi (see one of my previous posts). All that works till some degree. But at no time it was "working fine" for me. Best comparison which comes into my mind is with Russian cars (especially old): not that you could not drive them, but you could never predict either it will deliver you from A to B today without troubles.
 
MFX API has fundamental design mistakes in part of non linear functionality, in both Live and Recorded processing scenario. They was always there and they was always known. There are no changes with that during last 15(!) years (if I understand that right, since the introduction of that feature). No wonder there is just one CW Arpegiator MFX plug-in, I guess everyone who has tried to write something is that direction has realized the problems and has moved away.
 
At the same time, simple filtering/mapping/switching (where one event on input should be converted to the fixed set of  output events) works ok.
 
And so:
* mapping/filtering - MFX (stable and predictable)
* non linear processing and generators - VSTi in the synth rack (buggy, but somehow works).

I am not going to be able to shake the "old Russian car" analogy now...

My brain is like an old Russian car. Apparently. 

Yeah guys! Never buy Russian car!! )))
I know what I am talking about... ;))