Once it’s in it has never dragged. I don’t know why they are not more popular.
We are so pleased with the purchased anchor, and will like to order an additional for our aft windlass.
I treated [boat name] to a Knox anchor this year. Digs in at first attempt, never dragged and a bitch to recover. The old CQR could usually manage two out of three.
Amazing difference in initial set and holding compared to the Delta
Previous anchor was a 25lb genuine CQR (32ft boat, 6 tons) and I have retired it in favour of a Knox 9kg, which fits the stem roller without any adjustment, save that I need to drill a new hole in the cheeks for the retaining pin. The Knox performance around Plymouth and up the river is amazing; just like a parking brake
I’m just back from a few days sailing off the West of Scotland. We spent two nights in near gale force conditions and our 13kg Knox didn’t move an inch - well impressed.
 I have spent some 5 weeks aboard the boat since fitting your anchor, with over half that time at anchor on a variety of substrates.  The performance is excellent,  thank you
Well it sure works better than the bigger Delta ! Anchored last night in more mud. Quite late, was getting dark, dropped it and bang stopped. Hm, surely that’s fouled :( Too late to sort it out safely so got up early this am to sort it out. Of course it was not fouled, it just held :)
— 8m motorboat, 9kg Knox
It is performing outstanding. We are currently in the West indies and have been anchoring ever since we left the Canaries last year. After anchoring we always dive down and check the anchor. It always digs in but sometimes it will not roll over to straight so one fluke will not dig in the whole way. At the moment we are anchored at Plage Malendure on Guadeloupe with wind gusts up to 52 knots but every time we check the anchor it has dug itself deeper in the bottom, which here is turtle-grass over sand with coralpatches.
We are happy with our Knox.
— 22tonne 46ft Bruce Roberts, 27kg Knox anchor

What some reviewers have said…

Alex Blackwell, author of “Happy Hooking”

Knox Anchor – an affordable choice for a comfortable night on the hook (coastalboating.net)

Steve at SV Panope, video of anchor setting

(4) Knox Anchor Testing. Anchor Test Video #98. - YouTube