These plugins are superb. The best there is in my opinion, especially for large ambient reverbs - Shimmer is excellent for this.
I use Ardour and Mixbus on OSX but really I prefer Linux. No Linux Valhalla plugins which is the main reason I’m posting here. OSX Ardour users can obviously try them. ValhallaRoom would be my number one choice choice for Linux then Shimmer. There is a survey you can fill in at ValhallaDSP. No harm in mentioning Linux. Developers think there is no demand for Linux because nobody asks. That situation may be gradually changing with Ardour 3 and Mixbus. I’ve already mentioned Linux to the Valhalla developer.
Out of curiosity I tried to see if Vahalla could be run in Linux as a VST plugin. First I tried running it with fst and I was able to use it as an insert in Ardour. It worked but there was no GUI so no parameters could be changed. Then I tried it as a plugin with a ardour (compiled for VST). Unfortunately, this did not work - no sound was produced when the plugin was active, but there was the Ardour-generated GUI for the parameters.
Next I tried Qtractor which was able to run Vahalla with both Qtractor-generated GUI and the Vahalla native gui. Seemed to work fine, was able change parameters,change the reverb characteristics. So, Vahalla VST is close to working with Ardour, and will work with Qtractor.
…later… I try Vahalla with dssi-vst and this works - opens GUI and can be used as an insert with Ardour.