I personally have not heard them, but i can offer some suggestions to ribbon tweeters in general.
Fact 1 ---there is no generality
Not all ribbons are created equal, and neither is the integration. I heard some good things about them, but if you give me your budget, musical taste, requirements then i can suggest a planar/ribbon/dynamic speaker that i feel will serve you best.
I can get hold of a pair for $1.400 (Aurum Cantus M-103). I believe the retail is $2000. My budget is $1.400-1.600. I listen to rock (Chilli Peppers, Foo Fighters, NIN, RATM), soul, a little jazz and a lot of hiphop...I've owned a pair of B&W's (601s3) and I'm not going back on that route...I'm ready to try something different - ribbon tweeter or not.
I don't blame you for not liking the B&W, they are the definition of colored. I do have some ideas for speakers, but please tell me what listening room you have. Also can you please post some technical data from the Marantz, espc. the damping factor.