I've had no problems with this update and my intel iMac running 10.5.6 and my TomTom 520. Generally, I have the impression that Tomtom Mac support has improved over the last year or so. I quite like the look of the software interface, although it's dreadfully non-Mac-like. But it looks OK and it works.

My biggest gripe with the Tomtom is how it doesn't work properly with the iPhone (but I'm not sure whose fault that is).