My point is that the default lack of precise automatic route data in Mapsource makes the Zumo less ideal for my usage since it will auto-recalculate me off my on-the-PC-preplanned preferred gravel/dirt-track if I deviate from said route.
This can be an asset if I ride my touring-rig Honda ST1100 in well-covered, paved road Mapsource City Navigator areas, but as you describe; all units share the same Mapsource data base. Therefore my prefs will be i favour of the unit which gives me better control over the route and map features.
To me the Zumo's excellent SirfstarIII antenna and MP3/BT/TMC functionality are worthless if the unit doesn't allow me to decide when/if the route recalc shall take place. Mapsource data in Southern Norway are too unreliable for my taste, effectively ruling out an Always-on route-recalc unit like the Zumo. It would drive me crazy.
I want a GPS navigator to make preplanned route & turn prompts along non-paved roads + I want to decide manually when the unit shall recalculate my planned route - not automatically send me back to tarmac or take unwanted shortcuts as it does now. Pure prefs favourizing the 2820 in my book. The Zumo doesn't allow this yet, but has other advantages (SirfIII/MP3/BT/TMC) for people riding on paved roads.
I spoke with Garmin yesterday and was advised that the "NT" version is the new version and offers much better compression than the non-NT version, which means a lot less memory space required for both.
That's correct, but the route recalc functions are the same, thus the Zumo and 2820 share the same map advantages or flaws. As a motorcyclist I don't need a GPS nav that automatically allows itself to send me up unwanted paths in unknown areas (Zumo) while route recalc and autozoom can be manually switched ON/OFF on the 2820.
So in a nutshell, according to Garmin, the map data is the same regardless of whether you have a Zumo or a 2820. However, the way in which the devices work are without doubt quite different.
As mentioned it then boils down to personal taste and user prefs.
If you want an easy-to-use GPS nav with flexible SD-card memory, excellent SirfIII antenna, MP3/BT/TMC and non-user-selectable route recalculation, go for the Zumo. If I only rode on paved roads I could live with the Zumo - in well mapped Mapsource areas providing better route data that is. As mentioned this unit can send a foreign rider ups some strange routes in Southern Norway due to several badly covered auto route districts. Not my choice.
If you want better control over map features (route recalc ON/OFF + autozoom ON/OFF) MP3/BT/TMC and can live with its fixed 2GB memory; go for the 2820. I certainly will consider the 2820 while waiting for a Zumo firmware upgrade - if it ever will allow me to control the mentioned map features.
The Perfect Motorcycle GPS is quite frankly non-existant. I could also fancy a 276c/278c, but that's another discussion.
To me the 2820 has the features I need while the Zumo is not as fit for my purposes for dirt/gravel-rides. I plan my routes beforehand and want to use the nav as a moving map as well as be able to control and set a fixed zoom level and turn off the route recalc function myself. The 2820 has a less powerful antenna than the Zumo but fits my purposes better.
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........can I interject with a simple question on the Zumo:
