WILL is spot on as usual, there are many frameworks but so much more is an engine. This is certainly one of the most feature packed pascal engines around (along with the honorable mention of Cast II and in a more abstracted way, GLScene). I work on my engine and I have to say that I learnt much from Reflos's Leaf 2, it's a well designed object orientated engine. I have learned that while flat functional programming in an engine can have certain advantages (many would argue performance and in given scenarios, learning curve), an object orientated approach can yeild after time, incredible benefits in terms of progress made and flexibility.

So in my humble opinion, if this is Leaf 2 plus a few more years in development, it will be by now a very capable engine.

I have not voted that I'd pay because my interests lie more with learning about and creating an engine. And assuming it had a price, I would concider first the already free Cast II engine and see if it had what I needed as it is also a very good engine.

However, Cast II does not yet have a GL renderer (but it has an abstracted design that facilitates adding new Graphics APIs)

so for the time being (if released) this engine looks to be one of the better choices for 3D, cross platform, fully object pascal game development.

GLScene deserves a mention because it too has facilitated quality 3d games. But I know of no current IOS developments and there's a lot of immediate mode GL2 design patterns, potentially hampering the implementation of GLES and GL3+ techniques so I personally don't expect to see such support for a while yet.