I have both the Cintiq Pro 13″ and the XP-Pen Artist 12 Pro drawing tablet monitor . i like using both but definitely prefer my Cintiq – i can’t quite put a finger on it but it just feels so good to draw on.
That said, the XP-Pen 12 Pro is an amazing device. it has no touch features and there’s a bit or parallax when the pen is near the edge; but it gets the job done and an awesome alternative.
if you can afford a Cintiq Pro 13, I’d say get that. It’s under $600 most of the time. I see the price hover around 400-600 on ebay and amazon.
But the XP-Pen Artist Pro line ( https://www.xp-pen.com/series/Artist-display.html ) is worth the money too.