1. From you comments, it seems that they have similar placement restrictions to other "panel" speakers in that they sound best 5' out from the wall which is a problem for a lot of people
2. Eminent Technologies seems to be well under the radar. Not many people have heard them and there aren't a lot of places to go hear them...so, for a home trial, its probably going to cost a couple hundred dollars to send them back if you don't love them.
3. If you buy a maggie and then decide in two years to move on, you will probably recoup 75% of your purchase price because of their repuation and strong following. I suspect that your financial risk is much greater with the E.T. LFT-8b
As to the "midrange" question...whichever combination of drivers/crossovers/boxes allow the reproduction of the piano, the acoustic guitar and the voice to be done in a way that provide the "your are there live" experience is the right starting point....but I think there has to be a recognition that the way I interpret/process the sound of a piano may be different than others...hence, why different solutions work for different people.