i'm immensely pleased with my nuvi. i have noticed a few quirks but i think that can be attributed to GPS tech as it exists today.

for instance, i was in boston the other day when i first turned on the GPS that day. as such, it had to acquire the satellites, and relocate to boston. i searched for a particular point of interest (restaurant), and hit go. boston is a clusterf- as far as the roads go, so when it initially located me, it had me on the highway instead of the road that i was actually on, which runs right next to it.

then when i started moving, it wents nuts trying to place me, but once it got me in the right spot, it never lost it again and remained right on, even when i couldn't tell which way the roads were crossing and going myself. i went off the path at least once and it recalculated immediately and correctly.

i think the mapping logic somewhat relies on the driver keeping to the right path to a point, as well as already being located correctly in the first place, but once it has that, then i think it moreso depends on the unit itself.

again, i think this is just GPS tech as it exists today, but some are better than others at handling those quirks.

oh, and i too have heard bad things with magellan.