Not even a Go user, and yet this is one of the best things I have read today morning. Valgrind is possibly one of the most powerful tools I have in my belt!!
C is the language that benefits the most from tools like Valgrind. It's just so easy in C to write code with memory faults.
Memcheck (the main tool) has shortcomings (very slow, does not detect all kinds of errors). Its strongest point is that it does not need an instrumented build. That can be particularly important if you have issues in 3rd party libraries that you can't build. Its other strong point is that it checks for both addressability and initialisedness at the same time.
My favourite feature is using GDB with Valgrind+vgdb. That allows you to see what memory is addressable and/or initialised from within GDB.
