My last self build was all JG with collets, and I had no problems at all with manifolds or anything else. It's all to do with correct installation and then it doesn't matter which system you use. I favour JG for DIY as it's much easier to dismantle joints, especially in tight corners. I used the first Hep system in the early nineties and it was awful, but they've all improved over the last thirty odd years.