Pulled the trigger when it was over $600, just to hear what electrostatic sounds like. At first time listening to Monolith stats, I wasn't blown away or convinced it'd be the greatest thing I'll hear.
One problem I notice is that the portable amp that comes with it doesn't have a volume control and clips when I use line out from a DAC. Maybe not a problem if you're using a mobile device that doesn't have too much power. Another option would be to use another amp or software to lower the volume. But I just feel limited because after a certain level, audio starts clipping.
Quick notes on how sound goes, maybe it's my personal preference, but I find the bass really_really lacking and sounding overall thin to me--bass alone makes it less enjoyable for me. Soundstage sounds fine, but I'm not convinced. I can tell sounds coming from here and there, but not so much for depth. Maybe I'm asking for too much! But yeah Monolith stats sound forward; at times sounds are too close to my face. Treble is very nice without revealing too much or fatiguing.
The pads are leather with soft foam inside and very comfortable to wear. After wearing for long time, my ears get sweaty, not sure if leather is doing a good job or because it was summer or because the cups are not very open and cutting airflow.
Build quality seems okay. My pair actually has a part fall off suddenly one day. The part is secured with screws, but the inside where screws are held somehow broke into pieces and can't be secured with screws anymore. Maybe the screws were too tight? I contacted Monoprice if I could get only the part that broke but didn't get a reply so I just strapped with a velcro and doesn't come off now. Nothing big deal.
In any case, I'm not very impressed overall, except highs and comfort, for over $600. At current price at $350 (October 2019), I'm still not sure if it's worth it even for people who'd enjoy its sound.
Now that I have STAX SR-L700MK2 and SRM-353X (which blew me and my bank account away), I'm curious if there's an adapter for Monolith's 5-pin DIN to STAX plugs and see if the sound will improve. . . .