I did a quick search on Uniseals and didn't see where many people had had problems with them. The few people who did, admitted that they thought it was because they had cut the hole incorrectly.
That said, I am probably going to use them to connect my two sumps. However, I will not be using them in places where standard bulkheads are normally used: drain lines, pump connections, etc. I
Here's why I say that. I would be scared to put torque or weight on the Uniseal like when you have lots of PVC pipe hanging from the Uniseal/Bulkhead and running to another location. However, in the application like mine and yours, going straight from one sump to another, I feel confident. Its only a few inches and there is no weight or torque being placed on the seals. And in my case, more than yours, there is almost no water pressure because my holes will be as high in the sumps as I can get them.
Any thoughts on this? Does anyone agree or disagree with what Im trying to explain?