A friend of mine got his MB-D200 on Friday, but of course, like me, currently only has 1 EN-EL3e battery. The "manual" for the grip is, to say the least, rather sparse and doesn't really give much information regarding how you can tell which battery is being used or how much total power is available. So, we started by draining my battery to about 50% in my camera before starting our testing. After putting my battery in the Right position, his was the Left, we could see on Battery Info that his battery was at 100% with 0 pictures, mine was at 50% with a number of shots taken, as expected. Unfortunately the battery indicator on the top LCD showed full. So, we then went on a "shooting and chmping" spree to see when the camera would switch to the second battery, watching the top LCD as well. The top LCD never changed, but when my battery went to 0%, per Battery Info, we saw shots start to appear on the left battery. I was at about 290 shots on my battery at this point, but at least 40-50% were using the internal flash and the modeling light. The grip itself is really solid, feels great, I am really looking forward to mine showing up in a few days. As advertised it switches batteries smoothly, this is all good. The REALLY BAD parts are that you can't tell without looking at the Battery Info via the menu which battery is being used, it does use the "most used" first, nor does the top LCD reflect the total power in the grip, it seems to disply the highest level in either one of the batteries. This can be very misleading, in my opinion. My friend has an email in to a Nikon resource now to try to clarify this more. This is one that really does beg for a frimware upgrade.