I have a 24 mm yaqi and it is very good. It will be a huge upgrade on the men u which is pretty poor (the men u was my first brush and I remember it shedding a lot and being quite lightweight). It will dwarf the men u in every aspect, size, weight, amount of bristle. The loft on my yaqi is about 55mm (the website says 60) and it's quite floppy but the tips are really soft. The monster may be a bit stiffer with the extra width and reported shorter loft. Anyway they are dirt cheap and really good performers so I would say go for it if you like a big brush.
The Yaqi brushes are very good indeed, but one of their 30mm knots will be huge. I can't imagine using such a giant when shaving my face and neck — the lather would probably end up everywhere except where I wanted it —but it might be good for head shavers.