I must be one of the few that never use a grip ... it makes little sense to me, and adds weight. I carry a few extra batteries, and never have a problem with power. Takes a few seconds to change out -- Course, never need flash much either ... so that matters.
I'm seriously considering the new version of 7D (?) whatever Canon calls it. However, if it's gripped, it's dead for me -- not only do I dislike the look (yeah, what should that matter if it works well) but the feel, and the weight turns me off ... and I'm not a 'weak lightweight' either. I shoot now with a 5DM3 and 7D ... and will move up to the 7D (?) if it upgrades sensor and speed enough, and a better AF would be OK, although I don't have any problems with its AF now??
I'm expecting it to improve the sensor quite a bit, and if not, that will shut me off too. In addition, I have no use for video or WIFI or touch-screen, so if those are considered upgrades instead of sensor improvement, then it's not for me. Sensor improvement and AF will sell me, anything else instead will leave me satisfied with what I have now ...
I shoot sports and moving wildlife with the 7D, everything else (pretty much) with the 5DM3... as a general rule anyway.