It's 45% stronger than 316 stainless of equal diameter and 1/10 the weight. It is also superior to stainless for applications where cyclical flexing or vibration occurs. Brion Toss wrote to size it for 2.5x the rated breaking strength of the stainless it replaces, for safety factor. I'm planning to replace 8mm stainless with 11mm (7/16) Amsteel. The % loss from UV is supposedly 20% after 5 years and does not degrade as quickly after that because the surface layers filter UV penetration (obviously there will be a great deal of variance with line thickness and geo-latitude). I'm at 40-degrees North and based on current info I'd go with 6 years scheduled replacement -- if in the tropics I'd go with 5 years. Take a look at http://www.colligomarine.com for Dynex Dux rigging ideas. If using it for running stays you can use the less-expensive Amsteel Blue the same way. The only difference is that the Dux is pre-stretched.

My fittings and materials will cost under $700 for two 57-foot stays, of which approx. $400 is the rope. The fittings are re-usable except the spliced-in thimbles will be replaced with the rope for logistical reasons (they're about $35 all-together).

The principal weakness of Dyneema is heat -- but that's not an issue for rigging. You wouldn't want to use it as a fire rescue rope or as a sling for heated objects.