MOTIF-Montage and Cubase

I am not sure if this is the right section of the forum for this. I have installed Cubase Pro 10 and I am a new user. I have two keyboards that I use. One is a MOTIF XS8 and the other is a Montage8. At some point I will get just a MIDI control. Which is what I think I will need to do to resolve this issue.

The issue: When I play a phase on the MOTIF, it absolutely sounds great. When I paly the same phase on the Montage, can we say, not so good. Either keyboard should not have an effect the quality of the sound being produced. Montage8 (brighter sound/over driven, hard to control key stroke articulations). MOTIX (smooth as silk, no issues, sounds great).

Anyone have an idea why the two keyboards would make such a difference?

Kind Regards,
Rob Hanson