I've been getting such a low response rate from neighbors I've attacked that I've actually starting keeping a list of attacks and payoffs, something I really didn't want to do. I get 50 nerds every 2 hours, plus I've been buying extra though I'm not going to be doing that in the future. I send a nerd to every neighbor as long as I can, and move backwards through the alphabet after the nerds are recharged.
Last night, I sent out all but 10 nerds to random towns and woke up to 300~ elixir and some gold (can't remember the exact amount, but nothing close to the numbers others are reporting).
Neighbors who attack are immediately revenged, but like I said, there hasn't been much of that. Most of the gold and leveling I've done happened the first day I downloaded the update and went kinda nuts buying nerds, an update-fueled donut-fest I won't repeat.