Those new settings look fun to play with, too bad I never use Quicksync.
Looks like the Rate Control part has different Variable Bitrate options in the middle row, Constant Quality options in the bottom row. Never heard of VCM before, but I guess its another Constant Bitrate method since its next to CBR in the top row.
The Constant Quality methods should be good for saving to disk. Obviously everyone will want CBR if they're streaming.
No idea on Accuracy or Convergence, but if you're familiar with x264 you should be familiar with Lookahead. QPI/QPP/QPB is how you set the Constant Quality (CQP), just like setting a CRF in x264 (except I don't know what a "good" setting is, I'd start with the defaults of course). Similar for ICQQuality if you have it set to ICQ I would presume.