I've had the GuoGuan YueXiao for a few days now. I was expecting a lot because of all the reviews, but at first I wasn't as happy as I expected. Out of the box it was too fast for me, I was catching a lot and the feel was very dry, sandy and airy, which I didn't like. However, it's got a lot better with about 1000 solves, and I'm actually liking it, but it still feels quite dry and not as smooth as I'd like. But maybe that's because I'm comparing it to my TangLong which has over 10000 solves, so it's really smooth and I really like the smoothness of it, but the speed could be a bit faster and that's why I bought the YueXiao.
Even thought I didn't really like the feeling at first and it was catching quite a bit, I got a new pb (12.27) on my 37th solve. After breaking in, tensioning and lubing I've got a new pb single, ao5, ao12 and ao100. I average sub 18 seconds.
The speed is perfect after lubing the pieces with weight 3 (quite a lot of weight 3, I tried putting a bit more lube to get rid of the dry feel) and tensioning it. It's a lot faster than my TangLong but I haven't had many problems with controlling it. Left hand algs and N perms (I use the Z rotation N-perms) are a bit difficult but I'll learn them. I tried weight 5 too but it didn't seem to do much, the cube just felt really dry and I hated it.
About the catching problem many people seem to have. At first I had a lot of those small catches, but now they are mostly gone after proper tenstioning and lubing. My tensions are quite tight. Before I tensioned it the cube catched a lot, flexed too much for my liking and I even had corner twists. I would recommend using tighter tensions. I have heard that sanding down the squared corners can help with catching, but I'm not sure if I wanna do that because that could cause corner twists, and I had some with looser tensions on this cube. And the catching problem is getting better, maybe it catches just because I'm not 100% used to the speed yet.
Corner cutting is great, it cuts almost anything, but that's nothing new, my TangLong cuts the same, with a little bit more force.
After using the YueXiao for a few days my TangLong feels even slower, but I still prefer the feeling of it (except the speed). If the YueXiao will get smoother with more solves, I'll absolutely love it. I'm getting better times with it so I think it'd be stupid to not use it based on the feel.
Overall, I think the YueXiao is a very good cube. Out of the box I didn't like it at all but after breaking in, lubing and tensioning it's getting very nice. People who like light and airy cubes will love it. Based on other reviews it's also very smooth, but I'm comparing is to a TangLong so for me It's a bit sandy and dry feeling, but it's definitely getting smoother. It's fast enough for everyone, maybe even too fast for some people. I don't have much to compare it to because I've only been cubing for about 3 months and I dont have many different 3x3's.
4,5/5
EDIT: Now my YueXiao is amazing, turning is buttery smooth, the catching is gone and the speed is perfect for me. If you don't like it out of the box, setting it up and breaking in makes it better.