Acoustic Research M6 Holographic Image Series?

I was looking at getting a pair of these, but wanted some information on them first. I was wondering if anyone has heard these before. Also, where were these in their line-up. Was this the top of their line? Just wondering how they sound. I know they have a different technology used than normal speakers or any feedback on any of the hologrphic series would be great.
The Holographic Imaging Series was introduced by Acoustic Research during the 1990s. The M6 does appear to be the top of the line. Here's a link to a marketing brochure:
I've seen that, but I was just seeing if anyone had heard these or had any experience with them. That is the only thing I had found on the web that even really had any information about them. Thanks for the help so far.
Yes I own a pair. They sound incredible. Very natural especially in the midrange. I bought them in the 90's and they were the best I had ever heard. They are a good 10-15 years old now and still sound good. I am using an old Yamaha M50 amp and denon turntable.
I'm picking up a pair tomorrow morning. I'll post back with a report once I get them fired up.

May be replacing a pair of Energy speakers if they're better.

I'm getting the M6s. Hoping for good balance in the sound with solid bass from the twin 8" woofers.

On a side note.. they're free! Thanks craigslist!