Randy - the dealer where I got my D7100 in Wisconsin will be getting the MB-D15 either Friday or Saturday. Unfortunately, they are just getting one of two promised by Nikon and that one is mine But at least Nikon is starting to get them out there.
Feels great, as one would expect. Balances well, especially with the 300/4 attached. It's a similar enhancement to the D7100 that the battery grips were for the D200/D7000.
VERY "tacky", in a good way, and nice ergonomics for my hands.
VERY solid, no rocking, and the whole package feels a tad lighter than my D7000 with B/Grip attached...
The D7100 feels VERY solid alone, and the battery pack extends this feel. I'm just going to use a battery in the grip because at the miserly rate power gets used up, I don't need one in the body itself.
Just assembled the MB-D15 to the D7100. Typical great Nikon build, very frim, no wobble or looseness.
Compared to MB-D11 on D7000: Slightly different shape,,, an improvement for my hands. The battery tray is not interchangeable with the MB-D11 even though they use the same battery. One nice change, the wheels for rotating the 1/4-20 screw are much smaller and less intrusive than the MB-D11
Arca Swiss plates: Tried a Kirk PZ-143 (not the L-Bracket) made for the MB-D11 on the D7000,,, does not fit. The MB-D15 is slightly wider, front to back. I have used a RRS BP-CS Multi Camera Plate, for a temporary solution until RRS goes into production on their L-Bracket plate. This plate is a good fit however, not contoured to custom fit the MB-D15 battery pack.