BBEdit's find functionality is _much_ better and doesn't require you to set up annoying project files. (Needless to say, BBedit is also well-supported.)

Textmate was an inspiring piece of software when it first came out, but it barely runs under Lion (I fired it up to verify that find-in-project was as I remember, and it crashed on the way out), and still has one-character-at-a-time undo/redo which is unbearable.