Harness Combos & Price
I have recently purchased a SOSpenders PFD harness, manual type. I single hand and agree that it is a must. I, however, got the manual inflation type since I thought the chance of me being knocked unconscious was smaller than the chance of me going over the side while attached to a tether (though of course I make every effort to have the tether attached in a fashion to prevent this). My thinking is that a auto-inflated PFD would make getting back aboard more difficult.
And... I have recently read of some unintentional inflation problems... which is why there is the new "Millenium" model now (quite a bit more expensive).
In bad weather or while single handing I intend to wear the PFD harness religiously. I also have a submersible VHF handheld which I strap to it, as well as a strobe. In my view, safety of #1 and I like backups for backups.