Ribbon midrange pros and cons


Ribbon tweeters are fairly common on some high end speakers. ...they sound great.....can anyone tell me why ribbon midranges are hardly ever used by some of the best speaker companies. ..what are the pros and cons? 
128x128vinnydabully
I live just 40 miles from where Apogee was.
I suspect they were not prevalent on the west coast because they were very expensive to ship and very fragile which would have added a lot to the cost.
Scintillas destroyed more amplifiers than any other speaker I know of which interestingly enough made them a very popular cult item. They were ok but not near as sonically correct as the Divas. If you did not listen above 95 dB the Divas were fabulous. Their real talent was in the mid bass region. Upright acoustic basses were unbelievably real on these speakers. Only electrostats are capable of that kind of realism. Magnepans come very close. 
All planar dipole speakers have significant acoustic advantages over drivers in a box. The only place they stumble is in the very low bass. A subwoofer array fixes that,
May have much to do with production costs and logistics for the mass market. Being an Apogee owner (Duetta Signature and Scintilla models) there is a reason (in earlier post)  why someone drove from Indiana to NY to get them. Yes they can be challenging to set up, yes they are obtrusive to some and yes the Scintilla’s are tough to drive. Once set up correctly they are quite remarkable top to bottom without subs, IMO. And just to strike some balance i do enjoy my old LaScala’s and my buddy’s Golden Ear Triton reference speakers. So many great and unique choices. But they are no Apogee...:). 

With the DSP sub/servo stuff today it will be interesting to hear how the new PS Audio AN’s sound with midrange ribbons. I am sure a great outcome.
Over the years I have owned Acoustats (3 panel model) then switched to ribbons, (Apogee Full Range) kept those for a couple of years, used Krell amplification as a logical choice, after which I upgraded to the Apogee Grand, a speaker way ahead of it's time, and for the few Grands still playing at this very moment, they will still be top contenders. I had to sell mine due to moving house, and the new house not suitable for these rather big speakers. After some years moved to a bigger house again, and currently again using ribbons, well hybrids. (Gryphon Pendragons). I have heard many speakers, but will stick with the hybrid combination. For those who believe that ribbons (Hybrids) can't be enjoyable, feel free to visit, it may change your opinion....
 I’m surprised that nobody mentioned Strathearns that address a lot of the problems mentioned. They are great from around 400 Hz on up.  There is no need for a transformer if you put a couple of resistors in line with the amp.