sol1684
http://vibed.org/features#fibers
It still doesn't go into full detail, though, and a dedicated article would probably be worthwhile to write.
The drawbacks today are in my eyes mostly the relatively minimal support for non-PC platforms and that a number of language features are not yet completely finished. But if the main target are x86 based systems and the use of cutting edge features is not the primary concern, D2 is a great development tool today.
* I can only really talk about my experiences going from C++ -> D, but it was a long process where my way of designing systems and solving problems was gradually altered in many areas - much to the better. And the immediate reward of course is the extreme gain in productivity due to concise syntax, fast compilation times and, last but not least, the lack of a need for header files.