I have both the built-in colour Satnav and an old tomtom700.
For ease of use, and practicality I'm afraid the TT wins every time.
The touch screen, postcodes, favourites, programmable Points of interest (that allow speed cameras), position of screen (just a slight glance off driver view line) and the fact that it is easily updateable on-line all make it a far more user friendly system IMHO.
The built in screen is bigger, but due to the age of the software, has less detail, it takes a definate "head down" movement to view. Setting a destination is a total pain, and IME many addresses are "missing", or not logically obtainable.
I agree a modern built-in Sat nav is probably better than a TT, but my car is 8 years old, therefore the SatNav is at least that, and probably older, and it has not been updated.
The TT is physically old, but the software and maps are new as I have updated at regular intervals. The latest Operating System and Maps were September 2008 (I'll shortly have even newer versions installed

)
Just my 2 p's worth .. nowt else ..
