When comparing GameSalad vs Leadwerks, the Slant community recommends GameSalad for most people. In the question“What are the best game engines for beginners and non-programmers?” GameSalad is ranked 29th while Leadwerks is ranked 36th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Cross-Platform
Pro No-code editor
Pro Has a Windows(.exe) version on par with Mac
The Windows version is now upto date with all the features of its Mac sibling.
Pro Multiple publishing platforms
Can create and publish games for iOS, Macintosh desktop and laptop computers, Android, Kindle, Amazon FireTV and FireTV Stick, Windows 8 and Tizen devices.
Pro Gamepad support
Gamepad support is available as of 0.13.3.
Pro Free standalone viewer app allows instant, live mobile device testing
The GameSalad Viewer is a free app available for iOS, Android and Kindle. Once installed on your mobile devices, you can deploy and test your GameSalad games live on any mobile device running the Viewer that is on the same local network as your dev computer.
This even allows Windows users to test their games on iOS devices without a Mac device and without any complicated code signing or provisioning profiles.
And, you can even take your games with you -- once loaded onto your mobile device, a history option caches recent games on your device without any connection to the dev computer.
Pro Allows you to focus on the logic rather than code
Since the user mainly uses menu options there is very little code needed to be keyed in. This makes the code very easy to read and understand.
Hence there are many help videos on youtube
Pro Extensive community of seasoned professionals for support
Extensive community of seasoned professionals in all disciplines (graphics, game design, animation, physics, music, video production, marketing, etc.) producing tutorials, videos, publishing tips, free templates and who are willing to answer forum questions and help newcomers.
Pro Powerful expression editor and functions
Allows you to create expressions on par with LUA (it's back end-language).
Pro Custom collision shapes with JSON support
Allows you to import JSON data for custom collision shapes to use with Gamesalad's implementation of Box2d physics.
Pro Easy to publish
Software prepares your app so you can just send it to Apple. All my games are reviewed with no problems.

Pro Drag and drop editor
The drag and drop editor makes GameSalad very easy to use, no programming experience needed.
Pro Great engine
Very quick to learn and great for making games. Community is very open and helpful.
Pro Very good entity system, did have GUI functions, easy to use terrain editor with vegetation system.
Good API tutoials, workshop elements which can be loaded from steam.

Pro Both Windows and Linux supported
Pro Built-in level editor
Has an acceptable 3D map editor that is easy to use.
Pro Versatile flow diagram script model
Leadwerks's flowgraphs 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 Community forum offers plenty of support
It makes game developing much easier if you have someone backing you up when you run into a bug or other issues, and get replies within hours .
Pro Decently sized library of tutorials for both Lua and C++

Pro Very clean and easy C++ API

Pro Lua scripting support
Pro Reasonably priced
Standard edition of Leadwerks costs 92,99€. Additionally, it often goes on sale on Steam.
Pro C++ scripting support
Pro Terrain editor
The terrain editor allows sculpting, paint, vegetation placement and importing of external maps. Especially the painting is done very well and can lead quickly to very professional looking results.
Pro Easy to use API and scripting language
Cons
Con Bad editor
There is no scene zoom, search boxes, or snap to grid. There is also no ability to focus view on the actor or use folders for file structure.
Con Expensive compare with others
There is no free version any more and it is very expensive compared with other engines.
Con Poor editor performance
Especially when you're working on a big project.
Con No scripting language or SDK
If a needed behavior is not supplied by GameSalad, there's no way to add it.
Con Product is suffering - Lacking company leadership and no voice from corporate
Some customers are currently in a holding pattern from the lack of support and messaging from GS corporate. GS is currently unstable and developers are waiting for another update that has been going on from 2015.
No word or message from GS corporate about timeframes or deliverables.
You can read the ongoing discussion here.
Con Product is in Limbo - company is lacking developers
Con Doesn't support Windows platform (*.exe)
Doesn't support Windows platform (*.exe)
Con Little to no support
This product relies on community support, although some members are helpful and quite approachable they don't like to share their secrets with people that are new to programming.
The product is sold as a Full featured platform but it seems to more in the Alpha stage of development as a lot of the good aspects where taken out in previous versions.
Con Has a track record of broken promises
Con Forums are poorly run and censored
Con Highly misleading advertising
Con Only prefabs made with the Leadwerks IDE could be used.
The two main problems for me is that C++ is not as easy to use like LUA. The IDE should also support C++. The secons is that only prefabs can be used which are made with the IDE. So you can not easy made a game that can be modded by the user.
Con Weak out-of-the-box AI
The only AI movement function is going in a straight line.
Con Very buggy
Leadworks is a not complete, it's a work in progress. As such many parts of the engine are clunky, especially the level editor.
