A big part of Conda's usefulness is not system-wide package management a la apt or yum or whatever, but being able to have reproducible, isolated environments f

A big part of Conda's usefulness is not system-wide package management a la apt or yum or whatever, but being able to have reproducible, isolated environments for scientific computing or other times when reproducibility is very important, and/or when you need multiple versions of packages for compatibility with other packages. I believe it uses virtualenv for this, but I may be wrong. Regardless, having this feature (as well as no interference with the system Python) is one of the killer features for me, and others I'm sure.