I've got Qt's front and rear on my D1 and can vouch for them being excellent. Good protection, the slider makes traversing obstacles much easier and safer, and a neat fit with good access to filler/drain plugs. The only clearance loss is the thickness of the material and the ramps front and rear mean it tends to ride over rather than snag. Good in sand for that reason, too. The APT ones are very similar to the Qt's and would definitely be my choice (Aussie made out of proper materials, good price, and APT are great to deal with - plus you can pick your colour). I don't like the 'cap' style ones personally as they only protect that specific area and can fall off or dislodge depending on how they are loaded, and they have no ramps. You never know what's lurking where you can't see it...
Spend the few extra dollars. Slider-type all the way.
Rear one is covered in oil (TC rear seal kaput) and the front is shiny because of the effects of 1100 sand dunes :D
