<I'm baaaaaaaaack!>
my finding have been found, and the news is dismal.
using the nuvi 350 in London/UK:
severe problems acquiring satellites; could be the urban environment....
could be poor antenna; could be . . . .
sitting on the bench in an open space park, acquired satellites.
while sitting on the bench my "location" started slowly wandering around.
at one point the nuvi had me roughly wandering aimless half a mile north of the bench my butt was parked on.
fascinating . . .
the UK OpenStreet map - as I downloaded, uploaded, employed it
- open to significant user ignorance and error -
is not routeable/searchable/<whatever the right term is>.
using menu functions "Where to" produced "Enter state name" oops. UK doesn't have those - nor could I get it to "recognize" anything like county names.
note that I should very much liked to have tested such functions before I left, but there's no way to do that on the 350 . . .
the displayed scale kept jumping from large to small / small to large. as a walking tool, utterly useless given the inability to keep an appropriate scale on the screen. this only adds to the utterly useless inability to locate an address.
eventually just turned it off and used the paper maps. way more easier.
note that as it is primarily intended for automobile use, my criticism as a "walking tour tool" may be unjustified.
so, I've reloaded it with the USA updated maps, and it's certainly a device I will be leaving at home, when headed outside USA.