Pro Great performance
Goji is an abstraction layer over the standard Go library (which has support for HTTP) and added Einhorn support. There's probably very little you can do with Goji that you can't do with the standard library and a bit of elbow grease.
This makes Goji an extremely lightweight and fast framework.
Con Doesn't add a lot of functionality on top of the standard library
Most of the tasks that Goji is used for can be completed with standard library support without adding the overhead of an additional external library and without having the risk of Goji development being abandoned one day.