Seems like a gimmick to me, but I'd be interested to hear from anyone who has actually shot them. The claims Ethics makes about their spinning inserts sound superficially plausible (increased arrow spin rate, improved speed retention, elimination of broadhead planing), but I'm skeptical about appreciable benefits in practice. I'd guess that the spin and speed increases would be negligible. Eliminating the need to tune broadheads is a big claim that I'd have to see to believe. Ethics makes vague references to tests, but they don't have any actual test data on their website.
The Snyder Core system is something completely different. It's a beefed-up broadhead mounting system for micro diameter arrows consisting of a hidden insert (HIT), an external collar, and a head with an elongated shank...no spinning components.
Even if there is measurable performance benefits, which I doubt there is I wouldn’t trade it for the structural complexity needed for the insert to spin.
Some juice isn’t worth the squeeze