I haven't used them myself, but I've been asked to remove a broken set. A customer came back to their bike and discovered that a thief had tried to force them and failed. But not before breaking both front and rear lever mechanisms. I got both off without damaging the rest of the bike at all, with a cutting disk in the grinder they come off in seconds. Anyone can buy a battery grinder for $99 and youtube has a collection of "bike thief being ignored" videos so I'd rate these as "casual thief" resistant.
Also, the "locked" mode is exactly like the "stuck" mode of a normal set of QR skewers. Unless someone knows that they're the special locking ones they'll just apply more and more force until something breaks. So every time you take it into the bike shop or put it on a vehicle you will need to attach a note to the bike to that effect. I hope they come with stickers or something.
Given that you're looking at spending money at all, I suggest something more effective. A set of Pitlocks cost about $105 from Peter White (US) or 95 euro from pitlock.de. And they're made from hard stainless steel so a cheap battery grinder will take a long time to grind one off.