FiiO amps cannot power the M100s. Save your money unless you want to go a higher-range amp.
A cheap amplifier will do nothing for the M100s. I learned the hard way.
You are talking crap here. I just recently bought a FiiO E6 and I'm using it on my M100 as well as my Sennheiser HD-280 Pro. Big improvement when using the E6 direct to a laptop or my smartphone. Although I'm not using the E6 when the headphones are plugged to a mixer for DJing.
I bought FiiO's flagship amp, the E12 Mont Blanc, and it did nothing but hurt my ears and increase the bass. Explain how I'm talking crap if I'm talking from my experience, since I've owned 2 pairs of M100s, 2 pairs of LP2s, 1 FiiO E17 and 1 Fiio E12 mont blanc?
If you're talking DAC, of course the sound will be better.
It's possibly through my experience that I didn't let the amp break in, idk.
I used the E17 with my LP2s, not a big improvement, but overall a good improvement.