Crotch Strap
While I respect the experience of some of the people who posted they would not use a crotch strap I strongly disagree. The straps are not uncomfortable if adjusted right. We've happily worn them every single minute we've been on deck while underway for almost 20,000 miles now. It is easy to slip out of a harness (or PFD) without a strap. Maybe not so much if you're well rested, in settled conditions, warm, etc but injured, unconscious, cold, etc you would be surprised how easy it is to slip out of an otherwise properly adjusted harness. All for lack of wanting to click a simple piece of webbing between your legs...
We have done experiments at anchor and underway to "test" this fact. We cover it in our YouTube video "Overboard" and there is an excellent discussion of this on the Single Handed Podcast (Episode 14) at
http://singlehandedsailing.libsyn.com/
If you're interested we use Spinlock Deckvest PFDs (that have built in harness and crotch straps).
With regards to the original topic we run the West Marine jacklines and remove them whenever we are at anchor. They have lasted with little signs of deterioration for almost 4 years now in the tropics. We run them from a D-ring we installed just ahead of the cabin on the foredeck to a hardpoint mounted on the aft end of the inboard headsail track. While underway we leave tethers permanently mounted to the jacklines on both sides of the boat so it is easy to unclip from a cockpit tether (with one tether "leg") to the jackline tether that has 2 "legs" so you can move around obstructions without being detached (or double click for extra safety).
The biggest issue is getting back aboard. It is hard to impossible to simply pull yourself over the rail, especially if you have a long-ish tether. We cover this in Overboard with a few examples of options for double handed boats or while in difficult conditions.
I strongly agree with the post that mentioned the Spinlock PFDs. They have built in lifting straps in addition to being light and comfortable. Plus they have self-activating strobe on a pylon that holds it above the waves, a clear spray hood so you can cover your face in strong winds and breathe more easily, and other very smart functional safety features. Not cheap but the price fairly reflects the quality, comfort, and function.