I have a couple of impressions for the UM Mest.
After listening to the UM for 7 days, I have noticed that I couldn't part ways with the UM Mest so easily. Yes. The sound quality is that good. The detail retrieval is top-notch. The oBravo Cupid and UM Mest are fairly similar in that department, but that's all they have in common. The sound signature of the oBravo Cupid is quite dry in comparison to the UM Mest. So the oBravo Cupid sounds artificial by comparison. The UM Mest is full of life, emotion, and energy. Yet it keeps its energy under control. As for the soundstage, it's quite large. Definitely above average. Plus there's lots of air flowing across the stage and this breathes life into the music. As for the bass, there's a moderate amount of quantity and the texture is smooth, yet the impact is solid. The detail pops out because of the octaves. They are quite coherent. It's very easy to hear the distinct octaves. Bass guitar performance is excellent. Especially with bass-centric soundtracks. The mids are forward. Not too forward. The clarity and transparency are excellent and the vocals are lifelike. The treble is also moderately extended. I don't hear a roll-off of any sort. I do hear a brilliance of some sort. A brilliance that's faint which makes the atmosphere shimmer, including treble.
As for the gripes:
I couldn't wear the UM Mest for extended periods of time. This is because the earpieces were a bit big for my ears. It wasn't extremely uncomfortable, but it did give me slight discomfort after an hour and a half or so. I need to mention that my ears are super small. So that's probably why I felt slight discomfort.
Another gripe I have is the left connector. I don't know if it's a universal thing for removable cables, but the left connector is more difficult to remove. While the right connector is perfect. It's not too hard or not too easy to remove. The resistance from the left connector makes me nervous when I attempt to remove it from the left earpiece.