I would add that proper technique (part of which is scope) the issue 80% of the time. I read notes from people on different forums saying they get their Delta to set correctly, and yet I have anchored in the same place, in some cases, or the same bottom type, in extreme conditions and the Delta held just fine. As many of you know, I have cruised our Hatteras up and down the east coast from Key West to Massachusetts a few times, plus all the side trips, anchoring in all kinds of bottoms with all kinds of wind and current situations; 44 different places in all, several of them multiple times for multiple days. Most involved a four times a day swing due to tidal current. Add to that use of a Delta or CQR throughout SW Florida and the Pacific Coast on various chartered boats. We love anchoring out, therefor we boat.
The "anchor du jour" is the Rocna. I was going to get one myself, but it woudn't work in my pulpit so well. Rocna is not shy about weight recommendation. They spec'd 110 pounds for my boat. The "up-one-size" Delta I got is 88lbs. People go out and replace their old anchors with Rocnas and rave about how much better they are, ignoring that in many cases their new Rocna weighs 50% more than their old Brand X.
Certainly big is better for cruising purposes, up to the point you can't get the darn thing up because the windlass doesn't work for some reason. Steve Dashew, the famous world wide cruiser and boat designer, says you know when your anchor is the right size when people walking by on the dock laugh at how huge it is.
George
Hatteras 56 MY
Delta 88 Primary (the anchor, not the car-- those were boats too!)
Danforth 60HT secondary
Danforth 40 tertiary/stern
Boston Whaler 130 Sport
some kind of little Danforth.. works great