Ribbon midrange pros and cons

I’m uncertain what Magnepan uses, but my guess is long, thin, planar magnetic drivers. (Though the new LRS may use ribbons - but if the conductor is bonded to a membrane, it isn’t a ribbon).

I did some research and Magnepan makes "true ribbons" (some of their tweeters), as well as "quasi ribbons" really planar magnetics.

I think the OP was unclear, and seemed to group all flat rectangular drivers as "ribbons." He mentioned the forthcoming PS Audio AN speakers, which are using planar magnetics (or maybe AMTs) for their midrange.

Having owned Apogee Divas for 16 years I feel a bit qualified to talk about this. There are very few true ribbon speakers on the market. Mostly you see small ribbon tweeters and for many of the you can get replacement ribbons. Magnepan has a tweeter ribbon replacement program. They will send you a new set of tweeters and you send them the old ones back. All for a minimal fee. They rebuild the old ones and give then to someone else. The magnet structures are very hard to damage and they essentially will last for centuries. All ribbons are very fragile. If your wife tries to clean the speaker grill cloth with a vacuum they will suck the ribbon right out of the speaker. Magnepan uses what they call a quasi ribbon for the mid range driver which is a mylar diaphragm with wires in it which is more like a planar magnetic driver. Much tougher. The Diva used pure ribbon drivers throughout and under the right circumstances they sounded wonderful. But, there were problems. It was hard to get them up to 100 db even with subwoofers.
The ribbons stretched over time. The ribbons were very easy to damage physically. My nephew kicked one of my woofer ribbons at the age of two putting a big dent in it. As soon as Apogee went under I sold them and put my old Acoustats back in service eventually solving all the issues I had with them. Good electrostatics are immortal. In order to hurt the Acoustats I would have to drive a stake through them and boy do they go loud. Magnepan tweeters are the most durable ribbons I know of and boy are they great tweeters I tried to buy a set from Magnepan and they would not sell them. I also think Magnepan makes the best dipole planar loudspeakers that are not electrostatic and they are absolutely a fabulous value. It is also a great company to deal with. 
Over all I think you are much safer with dome tweeters then going for ribbons with point source speakers. Once you go linear array then you can not beat Magnepan's tweeter until you go electrostatic. m

I have a pair of the Magneplanar Tympani T-IVa, which have the great Magnepan ribbon tweeter. I also have the ridiculously-overlooked and under-appreciated (not by all; they got a great review in TAS, and VPI's Harry Weisfeld loves them) Eminent Technology LFT-8b, which has a ribbon tweeter and magnetic-planar midrange (180Hz-10kHz, with no crossover!), with push-pull magnetic structure. Best deal in planar loudspeakers, $2499/pr.

Dear @bdp24  : The only model in the Apogee catalog that goes below 1 ohm was the Scintilla and paired with the Classé DR 3-VHC ( 25 watts pure class A with over a headroom of 6dbs. A true horse/voltaje power. ) performs just great

I owned that amp and had for a while the Scintilla ( from a close friend distributor . ) as a demo pair.

R.

Thanks @rauliruegas for that info. I think I’m one of the few planar loudspeaker lovers who never heard a pair of Apogees. For some reason they didn’t seem to be big on the West Coast; I never saw a pair in any California hi-fi shop, Northern or Southern.