Maybe the Interlock gets more raves becaue it often looks prettier when found under the hide on the far side, a classic mushroom back to the Interlock ring. The Sierras can separate--though as you noted, this usually happens do AFTER they have done their work.
Though not always. About 35 years ago I shot a muley buck bouncing up a slope about 100 yards away with a 130 Sierra from a .270 Winchester. The bullet entered at the rear of the rib cage, and the buck dropped right there. Only when skinning him did I discover the jacket just inside the entrance hole, against the ribs. The core had gone on into the chest and killed him, pretty much instantly.
At the time, being somewhat naive and a new student of Bob Hagel's book, I thought the bullet had "failed." But I have never seen the jacket leave so early in a great many Sierras since--though often when the bullets are found under the hide on the far side, the jacket and core are not connected. But they are generally together, more or less, and there is a nice big hole all the way through the dead animal.
Somebody else mentioned the ProHunter (flat-base) versus the GameKing (boattail). The general belief is that boattails tend to separate more easily, because the tapered rear of the jacket doesn't grip the core as well as a "square" rear. I used to believe this myself, until one day when I went through all the recovered bullets I've filed away over the years in a couple of big tackleboxes. There are a quite a few of these, and it turned out that twice as many FLAT-based bullets had separated jacket from core as had boattails. So I quite worrying about it, and since then have used whichever one shoots best.
