The final Moto Extra operates in tandem with a desktop computer. When you find a destination in Google Maps, you can select the Send option. Motorola sat-navs will be one of the options, and all you need is the serial number from the bottom of the TN550. The destination will then be available next time you update the Google Location folder within the Favourites section. This is not a facility most people would use every day, but it will be really useful if you fancy planning a trip via a more friendly desktop computer interface, or need to send someone a destination whilst they're on the road. Taxi drivers could find it invaluable, for example.
However, you only get 90 days of Moto Extras out of the box. A year's service is then £29.99, with discounts available for buying more than one year. This is relatively competitive, but it doesn't include traffic updates, which don't come as standard at all with the TN550, unlike the TN760t. They can be added with the professional installation kit, but this is likely to double the price overall.
Also, whilst the TN550 still has voice activation, its capabilities are not as extensive as those of the TN760t. A single touch of the screen enables the system, after which you're presented with a list of options. However, you're only able to navigate to favourites, recent destinations or your Home location - you can't enter a new address verbally.
In use, the TN550 provides essentially the same experience as the TN760t, minus the extra wideness. Spoken commands are clear, but bookended by an annoying chime. Junctions are illustrated by iconic lane guidance, with the occasional full-screen graphic for particularly important motorway interchanges. The TN550 lacks the 3D landmarks of the TN760t, but we've never been big fans of these anyway and you're unlikely to miss them.
The Motorola Motonav TN550 is a more keenly priced proposition than the TN760t. However, it's still a little expensive, when you can now pick up TomTom's XL Live with a year's service for around the same money. Since this includes the invaluable HD Traffic, we'd have to say that the TomTom is the better buy.