I've been using the Tough Phone Defender Pro for over 3 years now. It's waterproof, has a good camera, independent GPS and holds all the OS mapping for the Uk. Extremely helpful when I changed my LEJOG route, earlier this year. It's nice to carry just one devise instead of three.
The phone has been with me on The Cape Wrath Trail, TGO Challenge and my 1200 mile LEJOG and 3 peaks walk. I recommend it but it is slightly larger and heavier than some phones.