Agreed, although improving load times all across the board is surprisingly helpful. It can make restarting your app in production after a deploy faster, for instance. If anything it just makes you happier in dev if you're running some Ruby command outside of Spork or Zeus.
I'm not sure if I fully understood your comment - You've used Zeus in production?
If in reference to just improving speeds all across the board - recovery after deploy is the #1 priority for me. Rolling restarts feel like unnecessary complexity in deploys.
