I quite like Vagrant myself but my primary complaint is that I seem to spend a lot of time waiting for VMs to start up and run a lot of bootstrap code.
You're linking to the wrong thing. This is the proper comparison to Tug: https://docs.vagrantup.com/v2/docker/index.html
Re your complaint: with the Docker provider, Vagrant only spins up _one_ VM (if you're not on Linux). After that, `vagrant up` just executes `docker` directly so there is no waiting around for bootstrapping. It even detects if you have Docker installed locally or not to decide whether it needs to run in the VM or not. And, if you're on Linux, it doesn't use a VM at all, unless you're on a kernel that doesn't support Docker, in which case it automatically/transparently starts the VM.
EDIT: Responding to David's comment below since it would go to deep: Vagrant is basically the same here. It doesn't require Dockerfiles, you can just spin up images.
Tug is a simple tool that I wrote to scratch a personal itch around working with dockerized applications and trying to optimize for startup speed and writing as absolutely little configuration as possible.
I'm hoping to get a few other people to try it out and let me know if it works for them and if it's useful, especially given the existence of so many other tools of this nature.