I was thinking getting the Siger plugin, since it was very recommended here in the Corona forum.
Siger is also great for this.
My only reasoning for using .mat files these days is I often change my plugins/workflow every few years and then my presets get locked up in software I dont use anymore, which is why I default to the host software. Im looking forward to materialX being the new standard workflow so I can just dump my current PBR libraries in that and use it universally for 3dsmax, blender, unreal, etc.
I started a Siger library a few years ago and dont use it now so I lost all my presets, dont get me wrong its a great plugin but I just dont need it for my workflow now so back to my old .mat workflow for now lol.