One difference, PE firms often load up their acquisitions with extreme debt.
Note that I don't own BRK shares; But I follow his investing methods.
My stocks are very much like his. I even have a good chunk of an insurance company, Dow component, Travelers. Two of my stocks have been owned by BRK. Two are aircraft related: Boeing and Rockwell Collins. I avoid cutting edge tech. My stocks are all large cap, or even mega cap.
And I change my holdings very rarely, mostly to realize a rare tax loss. Unlike many IHUBers I'm not a slobbering gambling addict.
No doubt Buffett would approve of my method, especially my decades-long use of index funds as my investing centerpiece.