I have a pair of them.
These boxes have been tested on Stereoplay/Italy showing ruler flat anechoic room response from 45 to 18 Khz. Attenuation is 12 db/oct under 45 hz, which means lot of output at 20 hz (think of walls/floor and even ceiling) in a real room.
MIL is well above 500 watts at lowest frequencies. If I remember well, the magnetic unit for woofer as the one for the mid and tweeter pounds over 5 kg.
The woofer is a pro unit, of which RCF is rewardered. The domes too come from their experience in horn drivers.
You can use even good small amps (mines ar now connected to a 35 w Linn Majik), but these are really professional Near Field Monitors, and you can drive them with a lot of power.
Voicese are really clear, bass instruments very dynamic indeed. Highs could be a little harsh if the amp is not smooth.
Only, be careful about interactions with the environment, because they could deliver really deeb and powerful low frequencies.