Leadwerks Game Engine is the easiest way to build 3D games. With a rapid development pipeline, support for Lua and C++ programming, and plenty of learning materials, Leadwerks is the perfect way to learn to make games.
The quickest way to summarize it I think, is that the engine is seemingly designed to slow down workflow in favor of looking complex and cool. I really feel like this was designed that so it looked really good in promotion, but in practice it's just not great. The wording in descriptions and the site is very particular, making the engine sound far more pleasant and robust than it is (though I suppose you can't expect developers to do anything but that). I mean, really, "Our renderer redefines realtime with image quality more like a cg render than real-time games of the past." Come on.
First and foremost, the documentation is puny. It's hardly worth mentioning. You will be learning how to do everything through trial and error.
The few included functions and "features" are very basic.
UI:
The UI seems to be designed to look robust and complex and useful, as it's mostly simple operations spread out and often duplicated in menus. The console at the bottom isn't useful much of the time and there doesn't seem to be any obvious way of hiding it, and so a large portion of your workspace is taken up. All of the tabs at the right side of the window take up way, way more space than they require, using up even more space. Even after familiar with where everything is, finding everything still feels like a game of Where's Waldo. Don't even get me started on texturing brushes.
Asset Integration:
This is actually one of the few things that Leadwerks had me smiling about. Importing assets is incredibly easy and quick. The conversion from source file to engine compatible and usable file is so quick and automatic. I really, really like the integrated material editor. Props for this.
I've got a decent amount more to say, here: Goo.gl