The first, obvious thing you would notice is performance. A docker container typically starts up in a fraction of a second (whatever process is running inside i

The first, obvious thing you would notice is performance. A docker container typically starts up in a fraction of a second (whatever process is running inside it might take a few seconds more) while a vagrant VM has to go through a whole boot up process. Docker has a slight overhead on disk I/O, but it's still far better than a typical vagrant setup. A docker container has very little memory overhead beyond what the process is using vs vagrant requiring you to allocate a fixed amount per VM. It's completely reasonable to run dozens of containers simultaneously on a laptop all completely isolated. Doing the same with vagrant would require an enormous amount of memory. The bigger advantage is the switch in mindset that is much harder to explain or quantify.