1. Oregon 450 and a 650. Marks are 450|650
2. 8|6 – The 650 is easily the best machine, but it crashes far too frequently.
3. I use the free OSM maps from Talkie Toaster. 8/10. I also have the 50k OS maps, but apart from when you need to know where a footpath is, they’re not as good as the clarity is poor. Geocaches blend into the background.
4. Never used it abroad.
“Follow the arrow” has a lot of comparisons – the best guide is to play with different models if you can and get a feel, but all the Oregons are pretty good and support geocaching very well.