I bought the S70 after getting bored and frustrated waiting for stores to start stocking the S50. I didn't see the need to spend an extra £20 or so on European maps I'll never use. However, the money was burning a hole in pocket so....
I bought my S70 from a well known electrical chain who will remain nameless. While I waited for the sales assistant to find one in the wrehouse, another staff memeber asked why on Earth I'd ever want to choose a Navman. The reason is, I prefer the interface and you get more kit for your money than you do with a TomTom - and at the end of the day, Navman and TomTom use the same maps!
Mine is an upgrade from an old Navman icn610, and what an amazing change they've gone through! The touchscreen is very responsive, with crisp, clear images and day/night settings so you always get a clear view. You also get a choice of the colours used, so if you're a touch colour blind, you should be able to find a setting that works for you. The voice directions are nice and clear. It's great to see that now they direct you in advance where several junctions come together, whereas my old Navman would wait until I hit each junction before instructing me further.
The settings you can play about with feel almost endless, the directions for the most part are spot on (the McDonalds locations that come pre-installed are slightly out), and it looks and feels well built. My one niggle with it is, if you look at a route overview where you have several waypoints, while it shows them on the map, it no longer tells you which order they are in. As a multidrop truck driver, I used to find that a great help, as I could alter my route if I'd got a couple of addresses put in the wrong way round. Otherwise, after 5 weeks using it on a daily basis, I have no other issues with this at all. To paraphrase the sales assistant, why would you NOT want a Navmam?