What's the difference between python shebangs with /usr/bin/env rather than hard-path?
#!/usr/bin/python is hardcoded to always run /usr/bin/python, while #!/usr/bin/env python will run whichever python would be default in your current environment (it will take in account for example $PATH, you can check which python interpreter will be used with which python).
The second way ( #!/usr/bin/env python ) is preferred , as it's not dependent on particular installation. It will work for example with virtualenv setups or systems where there is no /usr/bin/python, but only e.g. /usr/local/bin/python.