Well my daughter has tested the rings pretty extensivley now and I think we can safely say that she thinks they are great
She has tried them with the airlock and experienced no real loss of suction. She has snoogled with them on and, whilst in the past she has always had to take the domes off after a couple of hours as the pain would wake her, she managed to keep them on for over 4 1/2 hurs and only took them off because she really could not sleep on her back any more, and needed to turn over. (this was with the airlock kit). The rings have not only fixed themselves to the domes but have also molded to her chest slightly too.
Tonight she tried the green rings with in the new design but in the old foam. She felt that the design was an improvement on her old rings but nowhere near as good as the new material. They were not as comfortable and there was more loss of suction over time.
The only slight negative is that she has a small amount of marking where the rings go. I think this is because she is able to inflate her breast much more quickly with the rings, does not have to use as much lotion, and can noogle for much longer and maybe has overpumped slightly as a result!
She cannot wait until Lucy starts producing these for the XL as she ofeten ends up in agony soemtimes after half an hour or so with these.
So a definate thembs up from her