When comparing Nez vs GameMaker Studio 2, the Slant community recommends GameMaker Studio 2 for most people. In the question“What are the best 2D game engines?” GameMaker Studio 2 is ranked 67th while Nez is ranked 89th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Active community
The community is very active, so if you ask for help you'll get it relatively quickly.
Pro Open source
Completely free, no need to pay for licenses.
Pro Cross-platform development thanks to the use of mono and xamarin
Nez is built on top of monoGame and can be used the make games for many platforms (Windows, Linux, Mac, Android or IOS).
Pro Quick prototyping
Pro Good user interface
Pro Well-optimized engine
Pro Has a trial version (but limited functions, can't export)
Pro Many unofficial tutorials
Most GMS1 tutorials are fine for GMS2
Pro Highly customizable IDE
Although users must work within the IDE and editor, GMS2 has many options to customize the look and feel
Pro Good documentation
Pro Huge, generous community
Cons
Con Just a framework
Meaning there's no visual scene designer so you'll have to write your own.
Con Not the best scripting language out there
GML is just weird; if you want to learn programming, it is not the best because it teaches bad habits and has many odd shortcuts and shortcomings that won't transfer to a real language
Con HTML5 export is buggy, doesn't "just work"
Con Quite expensive
Windows ($100) + HTML5 ($140) + Mobile ($400) + UWP ($400) is $1,050, plus $800 anually for each console export separately. But doesn't do anything any of the free engines can't do, and the stability and tech support aren't great.
Con Unstable
Users frequently report crashes and hangs, particularly when working with assets, and the software uses a complicated underlying meta-file structure that may become corrupted and cannot be rebuilt
Con Limited support for OOP
Con Small development team
The core programming team is only 5-10 people, with about 30 employees total, so bug fixes can take a long time to be addressed, and there aren't many official tutorials