I'm not sure how much you know about D but:
1. Somebody is working on improving D's GC as part of GSOC in the hopes
of making it able to be precise (from memory not 100% sure).
2. Only a few language features forces you to use the GC.
3. For most uses you are not forced to use the GC in any form especially
with the help of std.experimental.allocator.
4. Our GC is based upon the Boehm GC. Its old. Even the more recent
versions would be far better then what we have (we forked a long time ago).
5. The requirements for our GC is quite intricate. I.e. you can't just
pop in one that doesn't understand about our Thread Local Storage (TLS)
and stuff.
6. As said by somebody else we can disable the GC so it won't go ahead
and scan upon allocation (only time it does).
