The twistlock has held up just fine. I am not real happy with the pump choice. I will not use nylon thumbscrews ever again. They stretch too easily and that causes them to be rather cumbersome to remove. I would either use stainless or studs with wingnuts. Taking the skimmer body tube off is very hard on the fingers.
I would also refine the indexing method I used to drill the flange mounting holes. They are not perfect and therefore the flange holes do not line up in any random position like they should.