Funny this comes up. I use my R100 as surrounds in my 5.1 system but just the other day I took them down and brought them over to my brother-in-law. He had a pair of Acoustic Research Rock Partner speakers that I replaced the foam surrounds on the woofers.
We set up his refurbished AR speakers, which he hadn't heard in perhaps 10 years. He smiled and said they sounded "like new." Then I pulled my R100 pair out of the bag and set them up. The AR have an 8" woofer and 1" tweeter on an angled front baffle and are a sealed (acoustic suspension) design. The R100 are a 5-1/4" woofer and 1" tweeter on a conventional rear ported speaker design.
His eyes bugged out when the R100 started playing. He's getting a pair at that $850 price, he said it's just too good to pass up and they just kill his old speakers in a much more beautiful package. And he thought the magnetic grills were just the coolest thing ever.