I got mine this weekend and have used it once so far.
My initial impression: It's rather floppy, somewhere between a Muhle Silvertip and a Simpson Best Badger. The Simpson Best is probably the, uhm, best comparison I can come up with generally, except that the YaQi showed some noticeable scritch. I'll have to wait and see how it develops. Aside from that, the knot feels fine and rather big for its size, kind of a large mop.
One thing I don't like is the colour of the hair, especially with this very bright handle. It just looks, well, dirty. Maybe that's also why they don't call it a proper silvertip, but rather "Highmountain Silvertip"? I dunno.
(The hair looks more yellow-ish here than it really is due to the picture being lit by the evening sun.)
The handle sure is a beauty! Very comfortable, too. A real shame they didn't put in a nicer looking knot.
I checked out the specs for this. 55mm loft will always be quite floppy. Around 50-52mm max should give decent backbone. The whole point of High Mountain hair is that it should have soft tips. Hope you eventually enjoy it!
I received mine a week ago. After rinse it opens to a huge size. Three uses for now. I like it a lot. Soft but scrubby. I'm mostly a boar brushes guy but it feels good and generates a ton of lather. For the price it's unbelievable.