Exactly as @aniwolfe states. Looking at the impedance versus frequency chart on the ET website, you’ll notice the impedance of the LFT-8b remains above 10 ohms all across the spectrum, with the exception of dropping below 10 ohms only between 55Hz and 180Hz (the crossover frequency). Unlike Maggies, a good candidate for tube amps. I had already sold my pair of Atma-Sphere M60’s by the time I got the ET’s, but I’m sure they’d work great, especially on the m/t panels themselves (with as I said above ss on the woofers). In contrast, Maggies never rise above 4 ohms, dropping sightly below 3 ohms at some frequencies.
As far as sensitivity goes, we have to keep in mind that sensitivity measurements are always lower with dipoles than they actually perform in a room. Those measurements ignore the back wave, fully half the speaker’s output! Add 3dB to the stated figure. Still low, but not enough so to cause it to be extremely amplifier-fussy, unlike ribbons, which are low in sensitivity, low in impedance, and reactive in nature (magnetic-planars are pretty much a resistive load). That is why I cringe when I hear Steve (and others) characterize Maggies as quasi-ribbons. No, they’re not. They are planar-magnetics, with the exception of the Magnepan true-ribbon tweeter. The tweeter in the LFT-8 (reproducing the top octave only---10kHz and up, though with a shallow 1st-order high-pass filter) is also a ribbon, the midrange driver a planar-magnetic---as Steve mentions, push-pull in design (most of the Maggies are single-ended.).