Hema 4WD maps on iPad

Hello all,
New members here.
Just wondering if anyone has tried Hema 4WD Maps on an iPad (or iPhone)?

I like the idea of using the larger screen on the iPad when outback and was wondering...
1) How effective is the GPS is on the iPad?
2) How quickly does the screen refresh?
3) Does it track your position in a 'head up' orientation?

I'd prefer to spend $139 rather than $700 for the dedicated Hema GPS.
Cheers
Tony & Susie