While totally unscientific I did an interesting, at least to me, test today. I've always liked O1 better than A2. Most of the reasons are subjective and based more on "feel" when sharpening than anything else. O1 on a good translucent or hard black Arkansas is about as sinuous as is allowed in a work shop. It's a shame I use mostly diamond stones now, there is not the same feel with either diamonds or waterstones. The other reason is O1 matches my work habits better than A2, I like sharp iron, my sharpening bench is a step from my primary work bench and I do not mind honing often as long as it is fast.
Let's forget the above rabbit trail and set up the test. A couple of years ago, late one night, bored, surfing the Lie-Nielsen web site, I ordered a 4 1/2 bench plane with out thinking about the iron that would come with it. Lie-Nielsen, being the company they are, offered to replace it with an O1 iron free of charge but I got busy and time passed without my exchanging irons. Over the years I haven't used the Lie-Nielsen 4 1/2 much, it always felt too heavy and was hard to push no matter how much I waxed the sole. I would use my old Stanley 4 1/2 with a Hock iron or lately the LV #4 with the PM iron. Ah... hell that was a tasty looking rabbit....
Anyway, I was checking my planes for sharpness this morning and the LN 4 1/2 felt like it needed sharpening, I did and it still felt like it needed sharpening. Hummm, that's not good, what to do. I thought about finally ordering an O1 LN iron for it but that would take nearly a week this time of year. Then one of the Stanley #7s caught my eye, it had a Hock O1 iron and chipbreaker, I never use it, why not try it in the LN. Give you an ideal as to why I'm thinking about selling off some tools, the Hock iron had never been sharpened. The back and bevel were just as they were shipped from Hock and I'll bet that #7 had been on the shelf for at least 2 or 3 years.
I'll finally get to the chase, I sharpened up the Hock, resharpened the LN A2 just to be sure both irons were sharpened the same. BTW, my setting jig sets the iron at about 33 degrees, so it should be good for A2 as well as O1. Waxed the sole of the 4 1/2 and installed the A2. No difference, it still didn't sing. Removed the A2, installed the Hock O1, re-waxed the sole and Bob Wills lives in a LN 4 1/2.
Now the question is do I order an O1 iron from LN or just stay with the Hock. Whichever I finally have a useable LN 4 1/2.