Pros and Cons of Ribbons

I've been looking into getting a pair of VMPS RM-2's and would like to hear any comments or thoughts on these speakers or ribbon midrange and tweeter speakers in general. These speakers have a 12" woofer, (2) 7" ribbon mids and (2) spiral ribbon tweeters. I know nothing about ribbon speakers but have heard that they are very open, transparent and detailed and have exceptional imaging and spaciousness. Some say after listening to ribbons you won't like cones or domes again. This all sounds good, so what's the bad part?

Thanks,

Steve