Bill, I have run ML Vista's for over 10 years now. At one point I had 3 Vista's across the front (Left/Right/Center) and Scenerio's for rear in a surround sound setup. Powered by Classe or Parasound amps.
You indicated that you have never heard them before, so I highly recommend that you audition a set of electrostatics before purchasing. It always seems that people either love them or hate them. (Personnally, I love them.)
So, in general, for electrostatics...
The Good:
Treble and Midrange are hard to beat. Fast response time, clear and precise. They have a level of transparency that few other types of speakers can match. If setup right in the room, soundstage depth and imaging are hard to beat. And not only left to right, but being a diapole speaker, I have managed to even get a sense of height to the imaging. Very easy to get lost in the music. Great for either nearfield or distance listening. And depending on the type of music you listen to, they can be great fun.
The Bad:
You have to setup placement properly. Distance and toe in are important, but not difficult to achieve.
As a dipole speaker, you also have to make sure you have the wall behind the speaker treated with some (and I stress SOME) absorbation or diffusion wall treatments.
As mentioned, there is a bit of a timing/coherence between the panels and cone woofer, but I was able to get over that easily.
Lastly, as with all planar speaker, there are limits with handling high dynamic changes. The membrane can only move but so much air.
The Ugly:
They want power and CURRENT. Impediance can drop to below 1 ohm in some models, as you go up in frequency. So you need an amp that can handle it. I think the Rotel 1090 would be able to handle it, but you may find you need a bit more grunt. Most tube amps are going to struggle with it, especially at higher volumes.
And finally, as with most planar speakers, there is a small sweet spot for listening. Some will call it beaming, and when you get off axis the treble and midrange drop away very quickly. ML eases some of that by using a curved panel, but it doesn't eliminate it all together.
Your bio doesn't list where you are located. I'm in southwestern Virginia. If you are anywhere close, I maybe able to arrange a demo. If not, check the martinloganowners.com web site and see if someone else is close and willing.
Hope this helps.
- Jeff