Summary: Although it's bulky enough to require the dedicated holder kit, it is very useful in that it allows for over eight hours of continuous Full HD recording with the Panasonic HDC-TM300 Camcorder. I could not find any other power supplies that offer this shooting time combined with this level of portability. The price is high for the battery and holder kit combined, but it's the best solution for long continuous shooting at this time. Surprisingly light weight.
Pros: Easy to use, Low Weight, Portable, Reliable, Rugged
Summary: this is the battery that panasonic should have included as the stock battery with all compatible cameras. As it is, my hmc-150 came with a battery about a third of the size/capacity--almost pointless for this type of camera. But...I realize this is the standard practice for all camera manufacturers. Great battery life--I think I shot for over 3 hours on a recent shoot and still had some use to spare. Hope capacity holds up over the long term.
Summary: This is the largest battery available for the hmc 150. There is really no other choice. The smaller battery is pretty wimpy in comparison. B&H has a decent price, although Panasonic charges a premium for the battery.