I used it at the time of the library split (there was a split in the community regarding the standard library, where Tango was the alternative). The compile time features of D were fantastic and they are still unmatched; as an example: For OpenGL (back then OpenGL 2.x) I could define the vertex attributes and had them checked at compile time when I started to fill the data with glMap! D templates and compile time code generation are on a whole new level, although it made tooling more difficult. If you know constexpr in C++, then this is nothing compared to what D has to offer.
I so wish that D would have taken off :/
I used it at the time of the library split (there was a split in the community regarding the standard library, where Tango was the alternative). The compile time features of D were fantastic and they are still unmatched; as an example: For OpenGL (back then OpenGL 2.x) I could define the vertex attributes and had them checked at compile time when I started to fill the data with glMap! D templates and compile time code generation are on a whole new level, although it made tooling more difficult. If you know constexpr in C++, then this is nothing compared to what D has to offer.