When comparing MonoGame vs Buildbox, the Slant community recommends MonoGame for most people. In the question“What are the best 2D game engines?” MonoGame is ranked 9th while Buildbox is ranked 51st. The most important reason people chose MonoGame is:
Support for iOS, Android, Mac OS X, Linux, Windows (both OpenGL and DirectX), Windows 8 Store, Windows Phone 8, PlayStation Mobile, PlayStation 4, Xbox One, Nintendo Switch, and the OUYA console with even more platforms on the way.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Cross-platform
Support for iOS, Android, Mac OS X, Linux, Windows (both OpenGL and DirectX), Windows 8 Store, Windows Phone 8, PlayStation Mobile, PlayStation 4, Xbox One, Nintendo Switch, and the OUYA console with even more platforms on the way.
Pro Open source
All the code is available to you ensuring you'll have the ability to make changes when you need to or even port to whole new platforms.
Pro Well-known and documented API
The framework implements the XNA 4 API, so games made in XNA can be ported to other platforms using this. This was the same API used by the Xbox Live Indie Games platform so there's lots of documentation online for it.
Pro Managed code
By leveraging C# and other .NET languages on Microsoft and Mono platforms you can write modern, fast, and reliable game code.
Pro Good community
The community MonoGame has to offer is helpful and mature.
Pro Performance on desktop
The performance on desktop platforms matches that of C++, but you still get all the pleasant features that C# has to offer.

Pro Drag - and - drop editor
Drag - and - drop editor without writing any line of code.
Pro Easy to learn
Buildbox is a drag and drop engine, making it easy for beginners to pick up. There are many tutorials available to help get you started.
Pro Has many game templates
Buildbox has 20+ different game templates including templates for platformers, racing games and Flappy Bird clones.
Pro Built-in support for ads
You can add banner and interstitial ads from multiple ad networks, including AdMob, RevMob, Facebook. They can work with Amazon's, Microsoft's, Google's and Apple's app stores.
Pro Develop once publish everywhere
Exporting iOS/Android/macOS/Windows/Steam/Amazon
Pro Cross-platform
Cons
Con Slow rate of updates
Versions 3.9 is overdue by a year, and version 4.0 is set to release in 2040.
Con Non-Windows tools are a bit funky
Monogame support for Xamarin Studio or Monodevelop is a bit shaky especially for library references. Only good non-Windows IDE compatible with MonoGame is Rider and that costs money & isn't open-source.
Con Incredibly Expensive
$99/mo for full functionality probably makes this the least accessible piece of game development software in regards to price, all with a very limiting feature set.
Con You are restricted by it's limitations
For example, you can only make certain kind of games.
Con Not very powerful
You will be limited to using templates to build games.
Con Subscription Model
The two more reasonable price points limit the functionality of a software already far less powerful than many more cost effective alternatives.

Con Very expensive
Buildbox has a 15-day trial version, after that a $2675 license to use it must be bought.
Con Stability Issues
The software has stability issues on Windows, with the preview window causing program crashes when simple functionality is added.
