Rethm Maargra Speaker: High efficiency, very easy impedance, built for SET amps.

Have you heard them yourself George?  I have not heard the Maargra, but I have heard the cheaper Bhaava (also with fullrange driver and powered woofers), and I thought it was very good for the money.  It probably doesn't hurt that the Bhaava is quite nice looking.

I am a fan of low-powered amps, particularly tube amps.  I own three of that variety, the "biggest" weighing in a 6.5 watts per channel.  I've played my system with various solid state amps, and the one I liked the most was the First Watt J-2.  

It is good to see more efficient and easy to drive speakers coming on the market.  I do like a number of systems using full/wide range drivers, particularly when those drivers are actually used in multi-way systems.  For pure single driver systems, I like the speakers made by Charney, particularly when AER drivers are used.  The Cube Audio Nenuphar also delivers the goods one expects from single driver systems--clarity, vivid and exciting sound--but it has more of the roughness and peaky quality than the Charney.  I also like the single driver systems by Voxativ which also deliver the goods without an excess of bads.  In multi-way systems with fullrange drivers, I like the canoe-shaped speaker from SoundKaos.  I've heard quite a few custom-made systems using such drivers built by Deja Vu Audio in Virginia--my favorite utilizes an old Jensen M-10 13" field coil driver run fullrange, with a simple highpass filter to a tweeter; another uses a new G.I.P 4165 reproduction 12" field-coil to a tweeter.

I would venture a guess that there is probably not alot of cross shopping between Rethm and Wilson.

 I do like a number of systems using full/wide range drivers, particularly when those drivers are actually used in multi-way systems.

My Bache Audio Tribeca speakers use a wide band driver, sans the whizzer, augmented by a super tweeter and 2 woofers. They sound wonderful with my Emotive Audio electronics. Compared to my Audio Physic Tempo Plus speakers, they don't have the razor sharp imaging. Instead it's slightly diffused, which to my ears sounds more natural. My guess is you would hear similar differences between  Rethm and Wilson.

I have enjoyed owning several different highish sensitivity speakers and I have enjoyed owning several different Wilson Audio speakers. Horses for courses.

I heard the Baahva and it was not coherent.
At higher volume levels you can hear the cabinet vibrate.

I have owned a pair of Maarga which I thought sounded very detailed (and no cabinet vibration) Actually sold them and bought a pair of the Saadhana (top of the line in Rethm speakers) and have been nothing but amazed. I drive them with a 24 watt Audion KT120. I think sounds more detailed than my buddies B&W 800D3. There are  bass level control that goes from Lo to Hi; and a crossover frequency control that goes from 60 to 240 (Hz) with a detent at 120 on the back that need to be set to the listening room. If you don’t adjust these to your room, it can give enough bass to vibrate a little, but adjusting them will give plenty of bass and no distortion or vibration. If you can listen to them again and the owner allows you to adjust it to the room, I think you will be pleased (and your friend thankful)

I was hoping Charney was going to be at AXPONA and I don't see Rethm either.  I did hear a set of Tannoys that I thought sounded pretty good driven by Pathos.I also heard the Wilson Sasha/DAW driven by Audio Research and it was not the best sounding system in the dealership. After all these years and all the media love given to Wilson, I was disappointed. But that is just me.