When comparing Genome2D vs uScript + Unity3D, the Slant community recommends Genome2D for most people. In the question“What are the best 2D game engines?” Genome2D is ranked 47th while uScript + Unity3D is ranked 97th. The most important reason people chose Genome2D is:
It's the fastest gpu-based framework out there for flash. It's beautifully optimised. It has very low rendering latency, low level OpenGL calls that other tech simply cannot do (ie Unity) due to Stage3D, and thus can render a lot more data quicker
Specs
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Pros

Pro Lightning fast
It's the fastest gpu-based framework out there for flash. It's beautifully optimised. It has very low rendering latency, low level OpenGL calls that other tech simply cannot do (ie Unity) due to Stage3D, and thus can render a lot more data quicker
Pro Cross-platform mobile, desktop and web
Supports Windows, Mac OS X, Linux, iOS, Android, Web and native Flash.
And with the HTML5 export, it also potentially supports development for the Wii U :)
Pro Haxe!
Haxe is a strictly typed programming language that saves development time but still compiles high performance executables, and can build for tons of different platforms (flash, c++, html5, java, c#, etc.)
Pro Access to direct draw features
Has access to direct draw features so you can make you own rendering structures (scene graphs etc).
Pro Automatic dynamic batching
Automatically batch geometries with dynamic batching techniques (by using constant buffers).
Pro Component based architecture

Pro Automatically generates nodes for third-party script assets
uScript's nodes are a visual representation of actual code blocks, and it takes advantage of C#'s reflection capabilities to automatically create nodes for any scripts it finds in your project, regardless of the source. This makes it inherently compatible with pretty much everything.
Custom nodes can also be created by hand, for cases where the automatically created ones contain more elements than they actually need.

Pro Versatile flow diagram script model
Modeled after UDK's Kismet (the predecessor to UE4's Blueprint), uScript's scripts resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish.

Pro Generates C# source code
Nodes are translated directly to C# files in your project. This is great for learning to code, and also for advanced users who can use uScript for fast prototyping and then further optimize the scripts if necessary.
Cons
Con Lacks documentation
The API documentation is minimal, there's not many tutorials and the ones that are there are very small and only cover the basics. If you want to learn how to properly use it, you have to ask the community or read the source code and figure it out.
Con Not too many games to showcase it
Con Slow development rate

Con Not that easy to use
It's a lot more complicated compared to something like Playmaker. Same tasks take a lot more time.
