I went to the store to try the TWZ-1000 today by Zero Audio. I was seriously considering it instead of the NT01AX, because of the Class 1 power Bluetooth in it.
In the end, the sound was not comparable. The sound didn't get as loud, mids were muddier, highs were less extended, buttons push it deeper in your ear canal.
I also compared again with the MW07, and found their tuning and details to be really similar! I probably couldn't tell them apart in a blind test. Maybe a hint more bass on the MW07, but the mids and details/imaging/soundstage sounded really similar. The highs are also both well extended without being sibilant. Mids are super clear, neither forward, nor back, and very revealing. Bad recordings sound bad. Old songs that have the record-player sound has that sound augmented to the point of being annoying. Boosted bass on rap songs is very noticeable. Bass decay is a little slow next to the ER4 (not surprising). ER4 has the mids up front compared to the NT01AX, and a little more clarity. It is especially noticeable in hand claps and finger snaps. Violins and pianos sound more natural on the NT01AX though, and classical or movie soundtracks sound absolutely amazing on the NT01AX. Recent pop with a lot of voice work sometimes sounds grainy and annoying.
I started wearing my Shanling m0 in my shirt pocket when walking in the big city or at the train station, and haven't had a single drop-out since (about 20 cm away from both buds). In my pants pockets, it gets a lot of drops in a busy town, but none in my small home city.
I had a great experience with the Nuarl company as well, I emailed them about a missing pouch in the instructions, and they sent it right away. They also confirmed that they would personally take care of any issues for warranty even though I bought from a re-seller on Amazon, as long as I was in Japan. Overall, I think they are the best true wireless has to offer, along with the Mavins. MW07 sounds solid, but after using the Nuarls for a while, I might have a problem with the battery time.