to Zyn or to Yoshi?

Seen the video and read some pro comments about Yoshimi which I have never used before. For the sake of experience I want to load both of them to use with rosegarden. Is there anything that says one cannot be used concurrently with the other as well as with hydrogen, and qsynth/fluidsynth to name just two?  I've started working on an ab-initio doc surrounding but not limited to RG (did another a long time ago that's gone obsolete, it was about some usb interface). What are the practically significant differences between them? This project could take the rest of the year seeing that I have a million other things to do  :-(

ciao