Just spent the weekend testing a cheap 7 inch tablet running Oziexplorer Android. The tablet is a XGODY T73Q, cost $68 on Ebay paired with a Kingpin bluetooth GPS unit (cost around $28 from memory). I use Ozi on the PC & have converted the map files using Image to OZF4 program from the Oziexplorer website. Have loaded maps for NSW in 1:25000, 1:50000 base maps & 1:25000 topo maps. Will load other maps when needed.
Tablet cost $68
GPS $28
Ozi App $36
Maps Free
So for $132 have got a cheap & easy to use navigation system. I also run Oziexplorer on a 10 inch laptop, but find the tablet version easier to use on the move. With the Screen Designer for the Ozi app it is easy to design your own screens to use.
Happy with the way it works so far, will be interesting to see how long the tablet will last.