I haven't yet. I hope a good eco-system develops around them. My biggest gripe is that there are just too many approaches in Golang when it comes to the dependency management.
Definitely true, the hands-off approach they took seemed strange to me - as others make that one of the core tenants of the community early on. Since I have been in the ecosystem it's been `go get`, `vendor` directory, the various community ones, and now modules.