Travel Technology - WAAS ENABLED GPS vs SiRF III without

New TomTom Go 910 far as I know is not WAAS enabled but it has SirF III. Is a SirF III without WAAS as acutate as a WAAS enabled GPS without SiRF? Does SiRF come ith WAAS?

If I am not mistaken, TomTom doesn't need GPS because it has an accelerometer and electronic compass built in to compensate for the small differences between GPS and GPS with WAAS. Also, because TomTom can intelligently "lock" onto a road it doesn't rely on GPS as much as other devices. I've compared TomTom with several other devices and it really is much more accurate.

SiRF is far more sensitive and easier to lock than GPS with or without WAAS. However, I have a GPS unit with GPS and WAAS as well as a GPS unit without WAAS. In my experience the GPS with WAAS was not much more accurate than just GPS alone.

I posted a similar question at http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=53702. Answer was that WAAS adds little and that SiRF III connects well even in difficult areas.

A bit of exploring there on map quality issues left me wondering about the differences in Garmin and TomTom. I will wait until TomTom is out and see how others believe it does in real life.

Brightness is important to me. Existing TomToms do not get good grades there. If 910 has brightness issues I may wait until July for the release of the Garmin Streetpilot 550.

According to this review it has a new antiglare screen:

http://laptopmag.com/Review/TomTom-GO-910.htm