I've been using this for awhile now. I wouldn't be without it. It makes washing MUCH easier, not having to chase water spots. I can take my time drying.
Using a De-Ionizer with a PW is the most labor-saving combo I've used, making washing two cars alot less tiring. It'a a pleasure not having to chase water spots.
I only use my PW to do a full-wash on our cars now. I'll do the wheels first. on the body, knock off the big dirt, foam it, (get the mitts out for a contact wash using the foam already on the car)....
Re: Jaguar wiper replacement- I replace them in the off position, too. I've always placed a microfiber towel under the arm, just in case it slips out of my hand.
Six pads will make the job go much faster. A small bucket with a bit of P&S Rags to Riches solution in it comes in real handy for pre-soaking the dirty pads.