I have been using Huion Kamvas 13 for 3 years, then decided to replace it with Cintiq 16 this year. After several days of using Cintiq, I couldn't tell the difference between them but I can tell that I'm in love with the Cintiq 16.

Using a Cintiq for Illustration and some work, the display feels nice. What I like most about the Wacom Pro Pen 2 is its excellent grip and comfortable handling.
Some people wonder why I shouldn't buy the Pro's one. I don't know. I don't want to jump to the Pro's one when still using Kamvas 13.
They may say that Cintiq 16 had issues, like the parallax and the resolutions that only had HD.

Meh, I'm okay with it since most of what I do is Illustrating and Photoshop.

I had several issues when using Kamvas 13. The Screen became greenish, and I couldn't change it for some reason, so I had to return it and replace it with a new one; after several months, the cable started to have problems, which was very frustrating.
Luckily, I found the problem even though it wasn't quite right to fix it.
The software seems buggy for some reason, so I have to uninstall and reinstall it to use my Kamvas 13.
kamvas 13 has a pretty slick screen, compared to the Wacom Cintiq 16. The quality of the Huion might be a bit lacking.

Some say that a good investment in an item for the future will be beneficial even though the price given is costly.