Cocos2d-x and Cocos Creator vs RPG Maker VX Ace

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.

Built for ease of use to get your game made quickly!

Super high quality art assets get you making a game quickly without it looking terrible.

Get a ton of great assets for the community by the community through Steam’s Workshop support.

Never a shortage of user tutorials, assets, or support.

Quickly script simple events with a few clicks. This powerful part of the editor allows you to get through the tedious amount of content for quests and other in game sequences quickly.

Choose a tileset and get to mapping! Supported tiles will connect automatically to help you speed through the mapping process. Setting events on tiles is easy to do and populating your world with NPC’s and other items is easy to do.

Need more power for things like battle systems, plugins, or awesome effects? RPG Maker uses Ruby along with its own library to bring you the tools you need to stand out.

Everything you make is done through this powerful expansive database. You customize every character, weapon, enemy, and skill through this and so much more to make a designer's life easier.

Create things quickly with things like the character customizer or the experience curve editor. RPG Maker is made to let you change every single thing in your game swiftly and simply.

Although not free it doesn’t cost an arm and a leg to get RPG Maker VX Ace. You can buy RPG Maker for $69.99 or get a free trial to see if it’s right for you.