Just find by reference from Andrei Alexandrescu web site:
"Why a new debugger?" you may ask. The answer is simple: increased productivity achieved through a simple, easy to use interface and advanced features such as expression evaluation , conditional breakpoints, watchpoints, and scriptability.
Didn't test it yet, but make sense to try as GDB is.. hm... kind of powerfull but outdated... ( i used it "as is" and with DDD front end - but anyway it far from VisualStudio convininece )