I've got CoPilot and quite like it, works well.
Only issues I have with it are that because I connect my iPhone to my HU with a proper cable, I can't adjust the iPod controls with CoPilot, which is fine except it seems to mean I can't adjust how the voice commands lower the music/mute it etc, which means they play out a lot louder than the music, sometimes scaring the s**t out of me and sometimes overpowering the speakers if I've forgotten and turned the music up. Admittedly, these are partly my issues and may not affect many people anyway.
I've got TomTom v1.0 and that doesn't beat the latest CoPilot, not sure what the lastest version is like but TBH, CoPilot is almost perfect IMO and for £26 is a bargain.