When you compare the results, you can see why many cruisers carry 2 or 3
different anchors.
As Chuck said, Practical Sailor found that Bruce set well in different
bottoms, but it's holding strength was very average. The SPADE was more
difficult to set, but had the best holding strength once set.
Here is a down and dirty simple review of anchors:
Anchor Types:
Spade - Excellent but expensive anchor for all-round use. Aluminum
models are lightweight with excellent holding power.
Delta - Excellent all-round anchor.
CQR (plow) - Excellent all-round anchor.
Bruce - Good all-round anchor, but may drag in soft mud or sand.
Danforth - Excellent sand and mud anchor, poor in rocks or shells. Does
not reset well after wind shifts.
Mushroom - Mooring anchor use only, effective when extremely heavy, far
too heavy for use as an anchor on board.