Hello Chris,
Buying protection for your diffs is usually down to price.
Both the ones you suggested are good bits of kit and "do what they say on the tin"
I'd go for the full cover type if I were you.
The smaller "bonnet" type can come off at times as they only wrap around the diff.
It will really depend on how extreme you go!
Light 'laning would be OK for either,
If you do d bit more challenging stuff then get the full wrap around type.
Again, depending on how extreme you go...buy front and rear, also buy steering a guard.
Cheers..........
Ron.