I believe that SRS uses Satmap Active 12, a system that is on my own wish list.
For now though, I just use OS MapFinder on my Android phone.
https://www.ordnancesurvey.co.uk/shop/mapfinder
The GPS signal is located in seconds, it doesn't appear to be affected by adverse weather conditions, the clarity and detail is great, you can load pre determined routes, and also record routes.
The downside is having to purchase map tiles, which as far as I can tell, stay with the device, meaning that you could be screwed if you change phone ect.
edit... One other downside that I discovered recently when out for a ride, was that for some reason I couldn't buy a map that I required whilst out on the ride. I was able to buy it upon my return back home, but that isn't of much use.
I still often carry a paper copy, but trying to unfold and look at a map, on a damp and windy day, is no fun. Using a clear plastic map pocket also become a very quick annoyance.