I own a Primare I21 married to a pair of Proac Reference 8 Signatures. I can tell you with full conviction that the amp is a fantastic product with exceptional resolution, transparency and tonal quality. I am so happy to find this amp as I stopped searching and just enjoying my music collection. It is also amazing to realize that whether you listen to Alice in Chains or Patricia Barber or Mozart, the listening experience is always rewarding and revealing. I think a lot of people point out that the sound is on the polite side but I actually associate the politeness with a sound stage that is not thrown on your face like a cheap amp would do. Imagine a sound which is very transparent, airy and resonating, with lots of depth and deep base when it is called for. That is Primare.
It is in fact not surprising that BOTH Primare and Proac are not easy to find on Audiogon.