When comparing Gosu vs WiMi5, the Slant community recommends Gosu for most people. In the question“What are the best 2D game engines?” Gosu is ranked 50th while WiMi5 is ranked 70th. The most important reason people chose Gosu is:
Gosu is not a game development framework, only a media library that happens to be suited to game development. (Kind of like SDL in the C world.) That means the interface is relatively small.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Lightweight
Gosu is not a game development framework, only a media library that happens to be suited to game development. (Kind of like SDL in the C world.) That means the interface is relatively small.
Pro Mature API, actively maintained and developed
Gosu has been under development since 2001. It is mature and has several toolkits built on top of it to provide additional functionality.

Pro Cross-platform, even mobile, using Ruby
Pro Versatile flow diagram script model
WiMi5 integrates a powerful visual scripting solution based on Blackboxes that allows you to create the logic flow of the game. You don't have to code (if you don't want) but you can also do it. WiMi5's actions and behaviors 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 Integrated servers
WiMi5 provides integrated back-end services, with tools available to save game session data, manage rankings, etc.
Pro Free development
The WiMi5 platform is free to use, supported by post-publication royalties.
Pro Built in monetisation tools
WiMi5 provides features to manage in-app purchases and micropayments. Virtual Goods management is integrated into the Logic Editor.
Pro Publication partnerships
WiMi5 maintains partnerships allowing simultaneous publication to a number of Web and mobile stores, all managed through the WiMi5 platform.
Games can also be downloaded and publish it wherever you want: in your own server or with your own partners. Just check the Download feature in the settings of your game.
Cons
Con Deploying Ruby apps is a mess
Games built with the Ruby to .exe "compiler" do nothing more than extract your source code and Ruby.exe to %TEMP%, then run it. The code is not really compiled at all. The process for wrapping games as Mac apps is a bit nicer, but you'll need a paid Apple Developer subscription to code sign the app, or users will see a warning/error when running your game.
The only way to really compile Ruby is to use RubyMotion, which does not work on Windows and requires a paid subscription on top of the Apple Developer one.
(This Con is not specific to Gosu. Deploying Ruby code has never been fun.)
Con 30% royalties
For filling the engine, publisher, and back-end service roles, WiMi5 takes 30% of game revenues.
