Not officially 90dB (89 instead), the JM Reynaud Offrande is awesome, and with at least my version, they can be driven great with very little power due to a very flat impedance curve. I am currently driving mine with Wyetech Lab Onyx monos with their huge 13 watts of power, and have never encountered any problems. Also have had some friend's ASL Wave-8's powering them for a short time and although the amps sucked they never clipped or seemed short on power.
Bass hits down into the low 30's, however they don't have a big 100hz bass hump so alot of listeners feel they lack in this department. Me I can't stand speakers with that boost, so they fit me perfectly.
Very musical and emotional sound. Tone is top notch on them. Looks are outstanding, as is build quality.
And best of all at their going used price (if you want to go that route) they are a steal.