I've officially fallen in love with Zyn/Yoshimi. It is really straightforward (contrary to many proprietary VSTi synths) and powerful and I think it deserves much more credit.
I have still some minor problems but I think they are due to my programming of Zynaddsubfx and not zynaddsubfx itself.
I would like to ask, anyone has used Zynaddsubfx/Yoshimi for live performances? Is it stable enough (provided a stable operating system environment and a sufficient cpu/mem combo)? What are the physical limitations for such a performance for the various version of Zynaddsubfx (standalone Zyn, Yoshimi, VST Zyn)? Anyone tested it on a real environment?
I've not done any live work, but I have done very long studio sessions. I've only ever used Zyn & Yoshi as complete apps via jack.
The earlier versions of Zyn were not stable, and although I could get round the freezes for the studio, I would not have recommended it for live work. However much has changed since then.
I'm a bit out of date with Zyn so, although I know it is improved, I don't know how reliable it is over long periods. I can say that I find Yoshi to be stable for hours at a time.
With either of these, when working live, I recommend that you set up a group of patches on different channels (up to 16 obviously) then use several dumb keyboards set to transmit MIDI on the different channels.
The experimental version of Yoshi - 0.062 - does have bank and patch changing on-the-fly but I don't know how well this would work live (you would need a device to send the MIDI bank and program changes) or how stable it would be long-term.
I have used Yoshimi as my primary synth for a number of gigs. Very simple and easy to get back running if your system crashes (yet to happen at a gig). I have a couple issues with it's ability to recognize midi controller commands, but ease of use wins. Qjackctl, Patchage, and Yoshimi for software, M-Audio redium 49 midi controller, and now a pretty good laptop, Lenovo Y570 ideapad, running Ubuntu Studio. I was using a really crappy old laptop before which worked just fine.