Cocos2d-x and Cocos Creator vs RPGMaker

25% of iPhone games are made using Cocos2d-x.

This means you will not be alone in development, and will have access to a large community. You'll know you are developing for an engine that works.

Documentation includes a programming guide, API reference, video tutorials and massive reference test code project showing all functions and giving working code to the user.

A new feature since Cocos2d-x v3.1 is support for 3D models (in your 2D game), not only this but support for skeleton animations is included too! This awesome feature allows for impressive characters in your game along with easier, more fluid and realistic animations.

It supports Lua and Javascript with full feature support.
Especially with Cocos2d-JS you can develop games cross web and native, and the native solution have great performance with JS Bindings, much better than hybrid solution.

Cocos2d-x forums are active.

Cocos2d-x is not only open source but also supported by Chukong Technologies of China and USA.

Regularly updated and adding support for the latest technologies. 2014 has already seen the release of Version 3, a new Cocos Studio development toolkit (optional) and support for new technologies like skeleton animation systems Spine and Adobe DragonBone.

Cocos2d-x is C++ based engine and it has CPU advantages for most platforms because of that. It uses polygonal mesh methods for sprite rendering for using GPU advantages. (You also use quad methods for benefit CPU).

Because it is based on Pyglet.

On top of supporting pretty much all existing platforms (except consoles), Cocos Creator (Cocos's IDE) allows you to write 1 code that runs on Android, iOS, Windows, MacOS and HTML5 (not Linux though).

Through the use of SDKBox you can easily integrate 3rd party SDKs and plugins for each version of Cocos2D (Lua, C++ or JavaScript), you just choose the SDKs to integrate and SDKBox will do the rest.

For example, if you want to add a rating plugin, you use sdkbox::PluginReview::init(); and if you want to add the Vundle Ad Network SDK, you use the one packaged in SDKBox SDKBOX sdkbox::PluginVungle::init();.

It has a built-in Python interpreter that allows for easy debugging.

Cocos Creator (Cocos' IDE) comes with scene editing, UI editor, animations & particle editors and whatnot. It's also easy to use and pretty intuitive if you read the official documentation & tutorials. Way way better than the old CocoStudio.

Hundreds of video tutorials available.

It's possible to create a game with absolutely no art or coding skills, so even complete beginners can make something.

The engine has seen multiple iterations since 1995, so a large online community exists that is always willing to help each other out.

With a script editor that uses a modified version of Ruby, it's possible to go well beyond the traditional RPG with this engine. Note: XP and VX use Ruby, the latest version "MV" uses Javascript for scripting.

It's possible to use custom editors from the community, edit libraries,include libraries,etc (MV Only)

MV supports HTML5 exports, so it is easier than ever to make your game work on iOS, android, OSX,Linux or Windows.

The inbuilt database which binds to game saves or can be made persist allows great power within your logic. Also a plugin called 'Alpha.net' provides multiplayer. This combination can allow great customisation of the engine, allowing a powerful 2D game to be made with little to no coding experience.

MV Mapping uses an additional layer to create better depth.

You can now HTML5 export your projects, so you could theoretically host your game on your webserver, and have your friends play the game without ever having to install a single thing.

There are several versions of RPG maker, with MV being the latest and most fully featured: MV ($79.99), VX Ace ($69.99), VX ($59.99) and XP ($24.99), 2003 ($19.99).