I've heard some good things about the Nordic nRF51822 BLE solution. I'm still doing a fair bit of work on my actual firmware implementation before I get to looking at BLE, but I've got a devkit ready for when I'm at that point.
BLE is a *very* different protocol compared to Classic BT in terms of how it consumes power, so I think you'll find the results are quite positive.
Here's a very trivial, untested power consumption estimation for the NRf chipset:

As you can see, even with very high connection frequency, we still get about 9 days battery life from a 220mAh battery. If we combine that with USB charging functionality, which isn't *too* difficult to implement from my preliminary research, that seems quite acceptable to me.
The primary disadvantage of the proprietary protocols is a lack of universal support. I use tablets and iPads often enough that I think being compatible with those is a definite plus, and you aren't likely to find a Shockburst or other proprietary protocol that works with that sort of device.