The syntax is familiar and the ideas are familiar. You don't have to learn anything new (not immediately anyway) like you do in Rust (where you basically need to learn EVERYTHING new).
Where this idyllic scenario starts falling apart with when you start actually using it for anything half-serious. Some of the bits feel extremely unintuitive and the documentation is difficult to navigate. There are few examples and the tutorial is a bit spartan. For example, I needed a deque-like container (double-ended queue), but it took me ages to figure out that a) the language actually has one and b) how to use the bloody thing.
There is also a bit of schizophrenia going on, with the "new" ideas and the "old" ideas clashing in some places. For example, they claim that you can run D without a GC (the new), but apparently a good chunk of the stdlib requires the GC (the old), so you're stuck.
I find this all to be unfortunate because D, to me, feels like it could be a better, saner C++.