Go's advantage is that you can share data cheaply while retaining memory safety [1]. The disadvantage is that you have stop-the-world GC and potential for data races, so you must rely on the race detector. Erlang's advantage is that you have no data races and no stop-the-world GC (and Erlang's GC is easier to implement). The disadvantage is that all messages must be copied and parallel algorithms that require data sharing are more difficult to write.
There are hybrid approaches like Singularity, JS with transferable data structures, and Rust (disclaimer: I work on Rust). These systems use some form of static or dynamic access control scheme (for example, uniqueness or immutability) to control data races and perform memory management for shared data structures, while retaining Erlang's thread-local GC.
Go has gone the Java route (I find both runtimes to be somewhat similar -- well other than the whole JIT thing -- with Java some years ahead in terms of GC and scheduling), and I suppose that Go, too, will get a concurrent GC sooner or later, but even the concurrent GC on the JVM has a few stop-the-world phases.
Go's advantage is that you can share data cheaply while retaining memory safety [1]. The disadvantage is that you have stop-the-world GC and potential for data races, so you must rely on the race detector. Erlang's advantage is that you have no data races and no stop-the-world GC (and Erlang's GC is easier to implement). The disadvantage is that all messages must be copied and parallel algorithms that require data sharing are more difficult to write.
There are hybrid approaches like Singularity, JS with transferable data structures, and Rust (disclaimer: I work on Rust). These systems use some form of static or dynamic access control scheme (for example, uniqueness or immutability) to control data races and perform memory management for shared data structures, while retaining Erlang's thread-local GC.
[1] With one exception, the memory unsafe data race in maps and slices. See: http://research.swtch.com/gorace