You'll hear sparkle, something I call "treble percussion." There's a cool energy to unfiltered HF. The veil is lifted. It's worth it. The resulting sound is cleaner.
If you have medium-long hair I wouldn't recommend taking off the front cloth. If you do hairs get in and touch the driver = not good. I didn't notice an increase in clarity in the 2 days I had the cloth off (I broke them after 2 days). YMMV
Without the front cloth, your drivers are more exposed to hairs or just plain dust. The remedy is simple: Blow lightly over them and they're as right as rain.