There really aren't any differences. However, when you install VS 20xx, you get a bunch of dependencies and '.targets' installed for you.
When trying to mimic on a build machine, you may have to install some SDK's or even manually move over some .targets to get the build to work. Every blue moon, there is a .target issue that cannot be resolved on a non VS-installed build machine, which drives me nuts and makes me smirk at Microsoft.
Here are two examples from memory:
Do a search in the folder:
C:\Program Files (x86)\
for
"*.targets"
and you'll get an idea of what I'm talking about (in regards to the vs installed items)