realskiers

Michael obviously has more direct experience with the bindings so wait for his opinion.

What I have heard is that the biggest complaint with the older pivoting heel was a little bit of a vague or rubbery feel in the heel-piece (inherent in the way the heel releases).  The newer series addresses that to give a more positive feel (but maybe at the price of putting marginally more stress on the leg as it releases.

If you weren't bothered by this 'feel' on the older design then I would think it's fine to continue with that.  If you think you would appreciate the more 'clicked in' feel of the newer binding then that would be a consideration.  Both are excellent.