it would be nice if it could follow the route as created on the computer as the 2610 could
No-one has come up with an exact description how the later (routing) units - both Nuvis & Zumos - actually go about their import task. For those that started with SPIIIs, Quests & 2610s, etc, the process was simple; you created in Msource, imported the route and rode it exactly as created. If your mapset on the PC was exactly the same as the unit, inclucing the compression algorithm (NT/non-NT), then the unit would not recalculate and everything was fine. Until you went off route. Or planned on a different mapset. Then your mighty Quest would recalculate, and off you went down the nearest motorway.
Those nice Garmin people obviously thought this method wasn't good enough and, at the same time, their market shifted to the car user & away from us folk. We ended up with the Nuvi. Even the Zumo 660 is really a Nuvi underneath - it's very similar to the Nuvi 550. All the units are pretty much the same nowadays, though with different functionality. For instance, the ability to switch off Auto-recalc - the Zumo 660 can, the Nuvi 550 can't, the Nuvi 860 can, but the 770 can't ........
What's also changed is the route storage format GDB to GPX. It would have been nice if Garmin had explained the subtle (& not so subtle) differences between the formats, but we're finding out by trial & error. What I have discovered is that a lot more info is transferred with GPX files. The routing preferences, for example. In the good old days, if you had planned a route from A to B down the back roads, & your 2610, for whatever reason, recalculated that route then, if your preferences were set to fastest with no avoids, you knew it would take you to the nearest motorway. Now, plan a simple route between 2 points - first with avoid motorways & then again with no avoids. Transfer to Zumo/Nuvi but make sure the unit recalculates after importing the route from My Data. Observe, you still have one route which avoids motorways & one that doesn't. So, Mr Garmin has improved things, but we don't know the rules.
One massive advantage with the newer units is that you don't need an identical mapset on your PC. It makes no difference to the unit.
We need Pan European to tell us how these damn things really work. In the meantime, keep reading all the forums until you've worked it out. And, just when you have worked it out, you can be sure that the firmware will be updated & you will be back at square one.
Or, add lots of vias when planning, zoom in & inspect each & every one to make sure its actually on your road, then enjoy the trip
