The Amazon tablet I purchased has a GPS chip and it was plenty accurate. Matched my One Plus phone. It was also $90 not on sale and I got mine for $60.
Not exactly sure why one needs "rugged." It's basically going to hang on a mount. Shouldn't be flying around the cab. You might dismount it for taking into the house for preloading maps and coordinates...but again... nothing I see a need for "rugged."
"Rugged" to me are industrial electricians using a tablet to red line prints and reference drawings, inventory and code books while actively working in an industrial setting with big machinery, oil, water and other stuff everywhere and a lot of organized chaos.
I currently use Avenza for mapping, and a custom app my neighbor and friend wrote...Fall Creek Trash that uses the Forest Service GPS vector database to do mapping on and off line...we use the app for scouting and cleaning up trash...tracking volunteer hours and lots of useful things that generate reports for the Forest Service...which in turn gets us more funding.
I use Avenza for navigating roads and trails. It was great on the Rubicon trail...but the map we had could have been a lot better with obstacle identification (what's the name of this one?) and bathroom locations.
My ten cents.
I'm happy with the roughly $100 I spent on my system. I need to modify and clean up the bracket and I need to box out the airbag space to increase it's functionality... dedicated USB port for the tablet and some storage potential.
-Mac