Nothing is strictly better than Ack, but some tools beat Ack in specific ways.

ack.vim A vim plugin for Ack. You can use Ag with this plugin as well. Just open your .vimrc and add let g:ackprg = 'ag --nogroup --nocolor --column' .

Exuberant Ctags This program builds an index of functions and variables. Searching is extremely fast, but limited to what's in the index. Good for very large codebases.