Hello Frankey:
Here's what I currently use and am very happy with the set up:
Tablet - iPad 12.9" 3rd generation with 1 terrabyte storage (immense amount of room for downloaded maps - important if you don't want to use cell data and/or are out of cell coverage). Big bright screen (although not bright in direct sunlight), easy on the eyes. It is a cellular iPad and I do have a cell plan attached to it, but it runs fine without a cell plan also. If you go into the iPad world you need a cellular capable iPad simply to get an integrated GPS receiver. Again, you don't need the cellular capability to be activated with a cellular plan but the GPS is really helpful. You can get by with a separate gps receiver communicating with a non-gps iPad via bluetooth or possibly communicating location from your phone's gps to the iPad via bluetooth, but I personally like have the iPad with it's own GPS for simplicity and it always works. If you want to look at maps without having your actual location indicated on the map then you don't need gps at all. However, that misses a lot of the functionality of electronic mapping.
Application - before I went down the Apple rabbit hole, I ran Alpinequest on a Samsung phone and Samsung 10.5" tablet. Happy with Alpinequest, but not so much the hardware for reasons I've described in other posts. Now using GaiaGPS and am very happy with it. Important to note that not everyone likes Gaia for understandable reasons. Possible that more satisfied users are on the iOS side than on the Android side. We have Premium subscription to Gaia for the variety of maps available there.
This is not an inexpensive system, but after a couple decades of various GPS units, mobile devices with various applications, tracking and mapping for three vehicles, three motorcycles, three bicycles, a sailboat in South America and a decade of GIS mapping work it is the system we've settled on for the foreseeable future.
Good luck!
Howard Snell