For the 7D I once bought a copy (made by Meike) because this copy decreed contrary to Canon original BG via a built-in timer (so, for example, interval shooting can be realized). The feel of this copy was but unfamiliar at first. She felt really after to from which it was made: plastic. And thus they did not fit the feel of the rest: just the 7D. Anyway, after a few weeks the whole labels of the timer had almost completely disappeared. As I pulled the ripcord, and bought the original Canon BG (and an extra timer for interval shooting ....). To make it short: the difference was (and still is after all these years still) enormous. Therefore, it was clear that for the 6D no experiments:
BG-E13 for the 6D
Just as I had expected: same processing and the same feel as the 6D. For me a real flatterer, and a tacky feel. The trigger and the other buttons have the same pressure points as the camera, and the fit does not show any problems: because nothing wobbles. Had me wondering, if it were not so ...
There's just no comparison to the cheaper BGs third party. Of course, these also fulfill its purpose (primarily ergonomics, especially in portrait photos), but in terms of quality and processing occur the differences apparent. For me, the phenomenon I carry my camera with a Sun-Sniper. This means that the camera is connected with the tripod mount on a shoulder strap. Since then also by 3 kg at the tripod thread pull (with heavier lenses whose Stativschelle is used, is not a problem). And if that weight depends on the thread of a cheap BGs ..., then I've got really no great confidence that that really keeps you in adverse situations. But even with tripod use in portrait format I would have in these situations simply getting a bad feeling. I've definitely not the Canon BG, I clamped the camera together with BG go there where it belongs, and makes me feel at ease. ;-)
In contrast to BG for the 7D is now pushes the batteries for the 6D by a rail in the BG. Because had I better like the old system: flap on the left or replace the battery right, flip. Here the carriage is just extended, and then you can replace the batteries. Is just a little getting used to.
If anyone needs a BG or not, is of course extremely individually. Although I do not have too big hands, but I had just always discovered with BG the better ergonomics for me. And the greater persistence without battery change for me is a big plus (pursuing photography semi-professional). Especially when one considers the features like WiFi and GPS, which claim more the batteries in use.
When 6D I had tried it for a while to do without BG. When occasional shooting that was not a big problem. When I but the Western Reining on the Schumacher Ranch in Givrins so about 4-5 hours was once the shoot (the first extended time with the 6D), I felt after actually my right little finger. Which lacks just simply a rest at the small 6D. And since I'm often shoot for several hours at a stretch on, applies to me "business as usual": for me means a BG a gain in ergonomics, such BG makes me the only camera fully. That's like saying individually, and each must decide for themselves. If you want to have a DSLR as compact as possible, it is of course a BG wrongly advised (hard to believe, but the camera becomes bigger ...)
This BG I can in any case safely give full 5 stars, it corresponds to the high quality workmanship of 6D.