It is better to have a messy but realistic history if you want to trace back what happend and who did and tested what at what time. I prefer my code to be clean and my history to be correct.
^^^ Couldn't agree more.
However, I don't know why people want to avoid rebasing feature branches. Rebasing feature branches means that you only have to resolve the conflict once and have a clean history for your release branch. Granted, it works well in my team where only a single developer owns a given feature branch.