Convolution IR's can sometimes be subject of great debate much like any app.
Espiegel from the Audiobus forum performed a detailed test comparing
Altiverb (a desktop only convolutution IR) , Thafknar and JAX Convolutor PE
which bore surprising results.
JAX Convolutor PE isn't available anymore but the pro version is.
Here's the link from the Audiobus forum for your perusal.
Also please add IR's and links to IR's that may sound interesting here.