what's the odds that psus outperforms brkb, 5 years and 10 years out?

I have no idea. But I do know that net PSUS return starts about 2 points behind Berkshire each year. In the end it'll probably depend on Ackman himself ... if he decides to put his "best ideas" into PSUS, it may outperform. But if he decides to put his "best ideas" in his personal account or some other unrelated entity, then maybe not. And risk-adjusted, it more likely won't outperform.

And really 5 or 10 years isn't the period I like to use to see who are the best of the best fund/money managers. I prefer at least 2 decades or so. So far only 4 or 5 people (managing anything of consequence) have stood the test of time (more than 2 decades) against the very common S&P500 index (Buffett, Simons, Miller, Danoff, maybe Lynch, Baron, etc).