I first used my iPhone 7 Plus which has quite a large screen,but find the iPad 4 mini awesome .....
you need the cellular one to get gps and able to load maps while away from WiFi .
i picked mine up cheap as I only fly the ps3 with it so didn’t need loads of storage ,mines only a 16g these are loads cheaper than the 32,64 128 etc
its still updating the latest iOS ,it’s now on 13.3 and still very quick......
my farther in-law has a samsung tab a with cellular ,I was like you thought I’d give it a go, I download DJI go,it ran very slow ....but did run/work.....but flight was scary! It was very laggy .... Dji was soon deleted off it and returned too the farther inlaw