I hear other cruisers complaining that they have to retighten their all rope halyards daily. I don't know what line they were using but it was the "low stretch" stuff - or so they say. I never have to adjust the halyard tension and I set the main for days or weeks at a time. A few years ago I gave a cruiser on of my old wire to rope halyards when his all rope one broke. He raved about how good the wire was compared to rope.

I am not saying that dyneema would be a problem but for the use and abuse my halyards get I'll stick to wire.