Solar 2D (formerly Corona SDK) vs RPGMaker

Corona SDK is completely free. That includes pro-tier plugins.

Corona SDK ships with Corona Simulator, which runs your game/app directly on your PC/Mac and updates every time you make changes.
It provides immediate feedback to your actions, you can see your changes right on the screen, without necessity to make build to device. Getting instant feedback really boosts tenfold prototyping and development speed.

It's easy to create a game that looks good on many different sized mobile devices.

With the live build feature, once you have created a build and installed on a device, you get lightning fast turnaround times because any change on the code or data is updated to the devices running the game (within the local WiFi) immediately. So changes can be tested on the real hardware within a very few seconds.
What's even more impressive, this even works flawless with multiple devices running the game. You have to use it to learn how good of a feature this is while development and even more, while doing QA. Imagine fixing bugs and everyone of your QA team/friends/whoever helps to get your game done, has all changes on his device without doing anything but waiting 5 seconds - outstanding.

Uses the great and easy-to-learn Lua programming language.

It's very quick to get things up and running with Corona SDK. The API is extensive and while it's not 100% feature-complete with the iOS API, it's close enough that you could create tons of games and never run into a roadblock.

The API docs can be found here.

Corona does not throw photoshop-like madness full of buttons editor. You can go as fast as you want, learning and building game from ground up. Eventually, you'll learn how much corona is doing for you. But to start you don't have to master complex editor software. It's a great tool to learn to start game development if you want to learn how to program and make games. Your experience will be 100% transferable to any other Pro game engine.

Corona works on OS X, Windows and Android (including Kindle Fire & Nook).

Since Corona SDK became Solar2D, it's completely free, as only some third-party plugins are paid.

Since Corona SDK became Solar2D, it's completely open source under MIT license.

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).