I feel compelled to respond to this thread after 6 years because when searching for "nicopress" and "standing rigging" the first two links on google bring you here (the first one indirectly). I'm not an expert, but I believe the nicopress fitting may have gotten the short end of the stick. Yes, they are ugly, but I believe they have a place on inexpensive boats where the owner would like to save money by doing his or her own rigging.
I called nicopress and I talked to a guy who is a sailor and he said the fittings are perfectly suitable for standing rigging and that the fittings are guaranteed to exceed the rated strength of the wire when properly installed. He stated he has several friends who use the fittings on their standing rigging and that the fittings are also used structurally on aircraft. He also said you need to use the copper or stainless fittings (not aluminum of course), that the plating needs to be correct for the wire type and the crimps need to be checked with a gauge to make sure they are within specification.
In my personal experience I've seen plenty of boats with these fittings on standing rigging in marinas, mostly plastic classics from the 60s with wire that looks like it could be original. Masts are still standing.
And what about england where they supposedly use nicopress more often? Are the winds really lower? I don't know, but looking at a wind map there are plenty of areas with 16 - 22mph winds today in the UK, higher than the 10kts here on the San Francisco Bay. How about the salinity? The map I'm looking at shows the salinity around england is average, and below average for most of the US coast. (see here:
http://www.coas.oregonstate.edu/imag...alinitymap.jpg)
So it seems if you have a nice boat and/or are having your rigging professionally made, than swaged is the way to go. If your boat is crusty, you want to do it yourself and you are strapped for cash, then nicopress may be your man. I do not believe using nicopress fittings is a safety issue if properly done.
Disclaimer: I am not an expert in any way, shape or form. I have never replaced rigging on any boat I have owned and I clearly have no idea what I am talking about.