Deploy: Ruby things. GEMs work better than EGGs, in part because there are fewer of them. Ruby makes OO easier.
Maintain: Python things. There are so many EGGs! If you need a new package for something or other -- the JSON parser isn't fast enough or something -- someone has made an alternative already. Performance matters for maintenance -- scalable deployment is still not easy, or cheap -- and it helps that Python has a fast core and syntactic shortcuts to things like generators (memory efficient) and list comprehensions (CPU efficient).
Maintain: Python things. There are so many EGGs! If you need a new package for something or other -- the JSON parser isn't fast enough or something -- someone has made an alternative already. Performance matters for maintenance -- scalable deployment is still not easy, or cheap -- and it helps that Python has a fast core and syntactic shortcuts to things like generators (memory efficient) and list comprehensions (CPU efficient).