The ONE and ONE XL design is much more stylish than the GO 510 and GO 910; I'd expect to see the 510 disappear into the sunset in the not too distant future, and the 910 to be replaced with a high-end version of the ONE XL.

I reviewed the TomTom ONE a few months ago, and while I loved the interface and some of the features, TomTom's use of TeleAtlas maps (instead of NAVTEQ maps, used by Garmin, Magellan, and most online mapping websites) proved its achilles heal, and prevented the ONE from achieving the high marks it would have otherwise received. Let's hope TomTom's recently updated maps prove more accurate and complete than the maps that shipped on the ONE.