I have been using the Garmin NUVI Road series for on road trips for 10 years now. All have built in speed readings. The current model I use lets me select Speed as the featured display. That screen also give you other speed data-average speed, fastest speed. That will scare you-"when did I go that fast?"

No map just number I prefer the dash/window mounts as I can mount the unit at the edge of my line of sight, and don't take my eyes off the road as in a in-the-dash mount

I used it in South Africa and UK as well as the US. I did have to buy micro SD's with maps for those places out side the US. I imagine the have dedicated AU units.

No subscriptions with mine since updates were included in the package price. Otherwise you do have to pay for upgrades. In the package deals when you update, your trip data-unidentified is uploaded and used by Garmin to update their map data base.

We had a new overpass and connecting street built in our small town that did not appear in the in-unit map. It appeared I was driving off road. I updated my maps and my data was up loaded. A few weeks later when I updated the wife's unit, that overpass and new street showed up in her unit. I also noticed on her unit a long driveway to friends farm, I drove up that had been "off-road" previously, now showed up as an extension of the road.

I reupdated my GPS and it also added the new street and over pass as well as my friends long driveway.

My current model allows me to select information fields to show on screen. I have current time. Miles to destination, Travel time to destination and ETA. Very helpful on long trips like the three day drive form Oklahoma to Montana for planning stops.