Geoff_K said:
Some will say yes, some will say no. I bought an off brand one for my D90 and it lasted 3 years. I know I would not pay Nikon's price for the one for the D800 and would buy an off brand, though might look for one in the $100 range after reading plenty of reviews about it on Amazon and elsewhere if possible

Nofai is right.

Looking closely at a lot of the off-brand grips, literally the only difference between brands is the price so be careful.

I believe there are only 2 models (china brand) you can buy . I tried both
the Meike one is fell like plasic but the button feel better.
the pixel one is better in material quality , but the button doenst feel good at all.

I returned the meike because it has problem, you can check my older post.
and new pixel i am using it now but sometimes i miss fire because of the button.

so , is the nikon made worth the money? NO , No , NO , NO
but should i buy the nikon one, YES ,
but the cost is too painful for me. I will stay with miss fire sometimes.

I'm not going to advise. I bought the expensive Nikon MB-D12 as I almost always do.

The MB-D12 includes a cut-out for the EP-5B power supply connector (on the corner nearest the camera). Does the XIT have the same?

Annoyingly, you have to use the MB-D12 if you want to run the D800 from mains power.

Some will say yes, some will say no. I bought an off brand one for my D90 and it lasted 3 years. I know I would not pay Nikon's price for the one for the D800 and would buy an off brand, though might look for one in the $100 range after reading plenty of reviews about it on Amazon and elsewhere if possible

Is this worth purchasing over the over-priced Nikon version? Seems too good to be true with the price tag of $60.