The GHB2 are the exact same as the GHB1 spec wise. They didn't make any changes other than a different tone of blue wrapping.
Is that true? I believe it could be, but people in the past have definitely believed GHB2s to be superior. Though the difference between a new and an old battery could be the reason for that, really.
Are you using the stock charger or 3rd party? I've only been using the stock charger with great results(3-4 chambers). As well as implementing the recent suggestion of easing up on draw speed when encountering the flashing blue lights. Are you getting a rapid flashing blue light immediately after a fresh charge?
Try cleaning your threads and battery terminals on the unit and batts if haven't already.
Don't let your batteries fully deplete. They don't like to be fully drained and prefer to on the charger.
Clean contact points/properly charged battery/draw speed = happy batts!
Cleaning contact points is an important point, and one I need to do a better job of. That said, the contact on my backend has some dark deposits that I can't seem to shift. I'll attack it with a little bit of iso alcohol soon, and see if that helps. I'm very happy with my GH, but it does flicker consistently when blue, and I suspect it's capable of even more than I'm getting from it.