is D worth learning?

The D programming language... is it worth taking my time off my current projects to learn?

I've actually found one independenet game programmer who uses D -- source code included with this halfpipe shooter called Torus Trooper is written entirely in D.

But will this language ever really take off enough to warrant learning it?  There aren't even any books on it, and that may be a bit of a handicap in really getting mentally "into" it.

OP here...

So D does have significant performance issues?  That's one of the reasons I'm also wary of C#.  C# does have nice features, but is not practical for anything other than prototyping or small/medium-small applications (nor was it intended to compete with the performance of C/C++).

How exactly does D have problems with recursion?  I'm not exactly an expert on writing compilers but I'm pretty sure recursion has been one of the more trivial and easy things for language designers within these last 3 decades...