I used ack-tmbundle before creating nice_find, and it drove me mad for two reasons. Firstly, the command doesn't work from the project unless you have one of its files open. Secondly, pressing the hotkey to bring back your search results will display a modal dialog over your results.

It's not the developer's fault, they did a great job. It is limitations of being a tmbundle. If you look on AIP's lighthouse page you will see that they can't resolve these problems. That's what drove me to write a plugin instead.

Also Ack (a perl script) is slower than grep -r and git-grep ignores all the irrelevant files. But feel free to fork it to use Ack.