I just got the TomTomGo, and am very impressed. The design of GO is top notch since it is specifically tailored for In-Car Navigation. Biggest reasons to choose the GO route are...
- The screen on the GO is amazing. Very bright with good contrast. Way better than any PDA I have seen.
- Voice assisted navigation. Most PDAs dont have speakers. Even if they do, they are not very good.
- Full screen is dedicated to Navigation (no other controls)
- GO device is meant for landscape (wide) viewing, PDAs are Portrait (high)
- GO has a "dock" which allows for integrated charging and additional accessories such as an external antenna. Hopefully they'll add TMC integration (US Maps CDs come with TMC code info)
Other than cost, the only reason other reason for the PDA route is if you really need a PDA. I have a PDA, used it alot in the first few months, but haven't used it since. Phones do most of what you need a PDA for.
Just my 2 cents.
Dan