Yesterday I moved the machine I use for Python development over to Manjaro as well. After running it for a while, I have to say it is a genuinely comfortable and stable system to work in.
Manjaro vs. Ubuntu
Back when I was picking a desktop Linux, Ubuntu was always the default choice. Its strengths are obvious: a huge user base, general stability, smooth performance, and the fact that a lot of software is packaged for Ubuntu first. But on my machine there was one really irritating problem — the screen brightness setting would not persist. I would adjust it, and the next time I booted up it was back at maximum. You can fix this through configuration, but even after that there were little quirks left over that bugged me. The other issue was software installation: the software center started slowly, and sometimes the install window would not even appear. Those few things left me less than satisfied.
Manjaro vs. deepin/UOS
deepin and UOS are among the stronger domestic Chinese distributions. The problems I ran into: deepin would occasionally freeze completely, with no warning at all — the desktop would lock up and nothing worked. UOS had the same issue early on, though the latest version seems to have fixed it. There was also a Bluetooth problem where it simply refused to connect to my mouse.
What I liked most about the deepin family was its terminal. It is designed very thoughtfully, especially when connecting to remote servers — among all the terminals I have used, the deepin terminal is the best.
UOS also has fairly high resource usage. Open a browser and leave it idle, and CPU usage sits around 5–8%; browse a few pages and it climbs higher, so the fan runs constantly. On battery, a full charge only lasted about three hours (Manjaro gets over five), which is quite power-hungry.
Where Manjaro Falls Short
There is no Chinese input method by default — you have to install one yourself. WPS fonts look very blurry. And the software store is not as intuitive as deepin's.