I just wonder how this codec will survive multiple generations of re-encoding (which is very likely in a post production environment.)

Can anyone with CINEC do a generations test and post the results?

HEVC (aka H.265) is a lossy CODEC, similarly to AVCHD (H.264). Lossy CODECs don't do well on repeated compressions (re-encodings). What we learned about JPEGs in still photography applies to these CODECs as well.

There are two ways to use such a CODEC. One is for capture, the other is for delivery (broadcast, or Blu-ray level disc if we ever get such a thing for 4k). For processing in between, you'll want to use a DI workflow, either a "we never touch the original footage" approach like Premiere Pro, or transcode to a lossless CODEC for all the DI work.