First of all, this is an old lens, why are you bothering to review it?
Second of all, where are the charts and maths that quantifiably prove that there is more magic in the 1.2 than the 1.8? My informal testing only indicates a 20% increase in magic that hardly justifys the price increase.
Also, why do you say it pairs with the 24/2.8? Everyone knows that the Canon budget triforce is the 28/1.8, 50/1.4 and the 85/1.8.
I like the 1.8 better than the 1.2 and the 1.2II. I've used all three over the years, and there are three things that I like about the 1.8 that you did not touch on in your review.
I will reiterate, I am not saying the 1.8 is better, and if you are looking for raw pixel-peeping image measurbating, get the 1.2II. However, because of the type of photography I'm paid to do, the 1.8 is better for my purposes.
1. Focus handling is generally better on the 1.8. The AF snaps quicker in general, and when I'm shooting people on stage or other people in motion in dodgy light, the 1.8 yields more keepers than either 1.2. Not to mention that while Justin mentions that you could do the same with the 70-200/2.8ISII by shooting at 1/13th, the people in motion part of the equation pretty much means that doing that isn't practical. Well, not practical if you want the people to be in focus. In fact, anytime you have moving people, the 1.2 lags behind the 1.8 The 1.8 is the better choice on the sidelines of a tennis or basketball game.
And while we are talking about the focus handling, the 1.8 is worlds better when using follow focus or otherwise using manual focus. Split-prism, live-view and video shooters know what I'm talking about. If you are constantly using the AF ring(5DII shooters I'm looking at you), 1.2II is fussy and annoying, while the 1.8 just works.
2. Minimum focus distance. Let me run some numbers by you; the 1.8 has a minimum focus distance of .85m, the 1.2II has a minimum focus distance of .95m, and the 70-200/2.8ISII has a minimum focus distance of 1.2m. This doesn't mean much to most people, and again, for 98% of the shooters out there, this does not matter. However, I frequently do tight headshots. (Just above the head to just below the chin with a little bit of collar showing) So, what does this have to do with minimum focus distance? Well, first of all, because of the minimum focus distance, this is not something that you can frame up in camera with the 70-200, because it will be too close to focus. You have to step back and zoom to 135 to get the same composition in camera. So, in this instance, you can't use the 70-200 @85 for the same shot. So, why use 85mm? Because your perspective comes from your distance to the subject, and your field of view comes from the focal length, and as soon as you back up and zoom with the 70-200, you have changed perspective vs what you would get with an 85.
So, anyway, with a minimum focus distance that is closer on the 1.8 than the 1.2, you have quicker fall-off in focus. (Macro photographers and focus stackers know what I mean) This means that if you get closer in with the 1.8 wide open, you can get both eyes in focus while the tip of the nose and the ears are out of focus, while the 1.2 pushes you back slightly, and you have to open up the aperture to get that same fall off, and it means that you typically only get one eye in focus on the 1.2 if you also want the ears and nose out of focus. If you want the medium format look on your tight headshots, the 1.8 does better, although you could probably get the same results by using a macro extension tube with the 1.2. That is, if you get a tube that doesn't kill the 1.2's focus by wire.
3. Borkeh and flare. So, I saw on dpreview a few months ago where someone did side-by-side comparisons between the 1.8 and 1.2 and said that the 1.2 had 35% better bokah. Really? You have chartable maths that tell you quantities of texture of out of focus areas? That's junk. The simple fact is that different lenses have different out of focus textures, and someone might like some textures over others. The 50/1.8 is known to have chunky bokeh texture, and in my opinion, the 70-200/2.8ISII has sterile borkeh. I don't like either.
So, in terms of bokeh, the 1.8 tends to smear the focus transition areas while the 1.2II has a more circular (rigid?) transition. When you combine this with the fact that the 1.2 tends to flare a bit more than the 1.8, it makes medium format looking tight headshots with a rim light crazy-making in post. What happens is the hair just behind the ears is out of focus, and the 1.8 will just smear and kind of pop it off the background. The 1.2II tends to flare the tips of the hair that is getting hit with the rim more than the 1.8, and you get these tiny little circular bokeh balls that are distracting. So, I end up having to go in post and clone out tips of hair. Really, nobody has time for that.