pipenv combine pip and venv. It's not just about activating. If you install, it will create the virtualenv if it's missing.

It also, like pew, opens the virtualenv in a new shell instead of activating the current shell. A much saner approach.

The UI is also more user friendly: one entry point for everything, pretty colors and icons, auto-correct of package name, and so on.

Using Pipfiles, instead of requirements, are generally a better experience than requirements.txt since it contains dev and prod dependancies and allow separated dependancy pinning, with file hash.