IMHO:
Pat's "lynch pin washers":
Pro: Handy in that, by design, they can't slide on the attachment's pin and stay in the right spot between the Pat's hitch and the lynch pin.
Con: Under certain conditions, with just the right force, and the right bump, (& a waxing moon when Saturn is in retrograde, etc..) I've seen these washers "pivot" and get past the end of the lynch pin, which sends the lynch pin flying, then one side of the brush hog falls off the 3 pth. Not fun when it's an hour past sundown and you're on the side of a hill. As a precaution, I use standard washers that can't do this.
(Another solution if using the "lynch pin washers", and this is hard to explain, is if you can turn the attachment's pin so it's the hole (for the lynch pin) is horizontal, then the lynch pin is blocked from inadvertently coming out by the "bulge" of the Pat's system where it goes over the tractors lift arm)
I've learned that part of my problem with Pat's is when you have multiple width attachments. Some of mine are Class 1, some Class 2. (Yes, I use proper bushings) The Pat's hitch doesn't have an equivalent for the swivel ball that's built into the end of the standard lift arm. This means when you mount the Pat's system, despite instructions, it doesn't have to be aligned with the lift arms so much, but had better be aligned to the width of that particular attachment, so that the pins of the attachment are at a perfect right angle to the pat's hitch. Otherwise, there's to much "sideways force", and lynch pin washers fail, and did I mention this is when the brush hog falls off...grrr!
I think for me, where attachments are different widths, this means I should realign the Pat's hitch depending on what attachment it's going on. Not exactly a quick hitch system if readjustment is required, but turning a wrench on the mounting bolts is still easier than wrestling a 1000 lb mower, or making 5 attempts to get tractor/attachment aligned.
I wish telescoping arms were standard. I actually though they were. Deere wants $800 ($400
ea) for telescoping arms! 40 lbs bar of metal with green paint. Expensive paint!
Also the mounting bolts than came with my Pat's System lasted about 2 hours running a 1100lb rotary mower. I don't think they were even Grade 2. Time will tell if the grade 5 (or grade 8?) I replaced them with will last.