I haven't used them but I've heard them, they're a very good midrange driver and pretty tough too. This is what L-acoustics uses for there midrange in there Vdosc professional concert line arrays. I heard them at a Don Henly concert here in T-town and the midrange was very very smooth at a live concert, so I can imagine what they would sound like in a home stereo listening enviroment. And everybody else I've talked to seems to like them and highly recommends them.
I used this driver in a Audax designed cabinet, installed in a small club several years ago. Used an audax tweeter crossed at 6000 and an audax 13 inch mid/woofer with the PR and sounded pretty smooth with four around the floor in the club. I still have a couple kicking around and would like to match it to a midrange conical horn similar to Wayne's because I used their 8 inch pro midrange in a conical horn and what a difference. Very efficient and much more powerful. Had to pad the pad the midrange when used with the Eminence 2001 as it's very efficient. I think this 8" audax is used the the Yorkville TX8. If you want a copy of the Audax plans using this 6 " midrange email me.