Up to 7.1
Apparently plenty of people had problem with iOS 7. Personally, I didn't notice as much. Most of the problem seemed to be from legacy apps, which were not updated for the new OS.
Today, Apple announced an update to 7.1. The updating process was painless, 268MB if I wasn't mistaken. No issues and the new OS seemed to be similar to the last one. Or at east I didn't notice the difference.
Maybe I should give it a couple more days to see of there were any upgrades in performance. As long as it didn't kill any of my usual apps, I wouldn't be complaining ...