I also have a nuvi 1xxx: 1340 and 1440 :
1) The searche for address works at least in my area of expertise .... but I have not tried, for example, in countries with place names in Cyrillic ...
2) the JCV (with JV in mode split for map NTU) works...but with fading .There is also a 3rd with my tests I posted as differences between NT and NTU (for JV)
3) routes imported from MapSource or Basecamp are truly absurd as processing
4) then ..... if you settle you and you'll be fine so ok, but you can not write saying that the maps NTU work perfectly on the 1xxx
5) screenshots available