The Quiksilver Synthetic Blend is the same as Premium Plus. They just went to a different label.
The Premium Plus does have different additives that Mercury Engineers decided on for best lubrication. The Pennzoil Premium is great oil, I know several people that run and love it. They say it runs a little cleaner than PP, less ash.
The cheap Wally world Tech oil meets TCW-3 regs., but I would run it. I blew a motor and know of a few others that did too running it. My thought has always been that if it's getting oil, any properly rated oil should work. I'm not risking it anymore... Powerheads are waaay more expensive than a decent oil.