I am currently on my second TomTom. The first is still going strong, but it's a bit bulky for use in the Morgan. I have never experienced problems using it, apart from driving in Zurich, where the network of overhead tram power lines completely screwed up the signal.
Route planning is easy using Tyre, and can be easily exported to either TomTom or Garmin - although annoyingly Tyre is a Windoze only app, so you have to run it in a VM if you use a Mac like wot I do.
