For example, read the Amazon Reviews. Things look rosy until you see what was actually written. The positive reviews often come from some clueless person who tells how good his 5D MK II product was and is not a review of the 5D MK III product at all.
Its like saying my 2005 Automobile was wonderful, so you will be happy with the newest model.
well i hope you don´t want to say all people here are clueless?
and often this is a amazon problem.
they mix up reviews very often or they get messed up when a product page is updated.
looking at the replys here at canon rumors, it´s clear that the majority is very happy with third party battery grips.
people who OWN and USE the grips.
the people that complain are usually those who don´t own or know the thrid party grips and only have "heard things". as you can see in this thread.