When comparing Stencyl vs Wave, the Slant community recommends Stencyl for most people. In the question“What are the best 2D game engines?” Stencyl is ranked 11th while Wave is ranked 33rd. The most important reason people chose Stencyl is:
Power users can also write code in Haxe (similar to Actionscript 3) to create their own custom classes and extend the engine.
Specs
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Pros

Pro Haxe scripting available for advanced users
Power users can also write code in Haxe (similar to Actionscript 3) to create their own custom classes and extend the engine.

Pro No coding required, great drag & drop interface
Visual scripting in Stencyl is based on the MIT Scratch project, which was designed to teach programming. Script elements fit together like puzzle pieces, ensuring that data and function types cannot be mismatched.
Pro Cross-Platform
Publish iOS, Android, Flash, Windows and Mac games without code.
Pro It's a NO-CODE Program, you can add logic without code
Pro The original concept for Ghost Song was created using Stencyl
The original concept for Ghost Song was created using Stencyl 3.x
Pro Great performance on every platform
Stencyl exports your games to native code so they have great performance on every platform.

Pro Extensive learning material
In addition to online API documentation, the Wave Engine team provides tutorials via IndieDB, plus sample projects and "QuickStarters" via GitHub.

Pro Supports coding in C#, F# and Visual Basic
Wave Engine explicitly supports all three core .Net Platform languages.

Pro Oculus Rift support
The Wave Engine team provides an official, open-source Oculus Rift extension via GitHub.

Pro Many components are open source
Several core components and official extensions of the Wave Engine are publicly hosted on GitHub.
Cons
Con Not a powerful engine
Should be used for basic games only.

Con Only available via subscription
There should be an option to buy it outright, especially considering it is written by a one man team....this is not exactly an Adobe level enterprise with shareholders, so there is no excuse!
Con Slow release cycle
Con Updated
It needs much to improve for mobile games, it was left in the era of Flash games. In Android you can not even put the native keyboard, you can not access things like native camera, GPS or native text input.
Con Tile system is somewhat inflexible

Con Mandatory splash screen
Games and applications made with Wave Engine must display a splash screen advertising it. No splash-free license option is available.
Con Not many tutorials available
Con Outdated UI
The UI looks like it is from Windows XP days. A refresh is much needed.
