With the staggering number of top-quality pens that you already own, I somewhat doubt that the Justus will really add something.
I’m looking forward to hearing your thoughts on it!
I finally got around to doing some initial testing with my new Pilot Justus 95 with barleycorn guilloche on the black resin barrel, rhodium† trim and rhodinated† F† nib.
I wasn't actually expecting it to be significantly longer than the Pilot Custom Heritage 912 — although I could have known that if I bothered to read the pens' specifications and compared them — but thankfully its barrel and section diameters are more or less the same as on the CH912. Even the barrels are the same length; it's the gripping section that's longer on the Justus 95 that is much longer, and consequently its cap is also longer to accommodate that. A plain black resin pen body with flat ends would have been utterly boring to me, and only "this much" better than a plain black cigar-shaped pen body, but the very subtle barleycorn guilloche redeems it, even though it's nothing like the pattern in texture and depth of the guilloche on the Aurora 88 Black Mamba (which I've concluded, after two foiled attempts to get it, that it isn't mine to have). As with larger ink capacity, "wetter" ink flow, and more "flex" in a nib, wider girth does not automatically mean a pen is superior or more pleasing to me; but I'm glad the size of the Justus 95 has not made it a distraction or annoyance to use for writing. I haven't tried suspending the CH912 and the Justus 95 by a rubber band to find their respective centres of gravity, but if anything, the longer gripping section housing the "extra" softness-adjustment mechanism probably shifts the weight balance forward towards the nib compared to the CH912, and that's a good thing.
In terms of the product's execution delivering what is promised by "what it says on the tin", and fulfilling what I imagine must have been the pen's design brief, I'd say it has done so astoundingly well.
There is some minor differences in how broad a line the user can get with different settings of the softness dial, but I'd say anyone who acquires this pen with more control (or a wider range) of "flex" — as if that was synonymous with line width — in mind would be utterly misguided, and through no fault of Pilot at that. What the softness control affects is the amount of pressure it takes to get the maximum "safe" spread of the tines achievable with this nib. It's almost the perfect pen for writing flair, if the range of line widths at the maximum-hardness setting on this pen already satisfies the particular user; the dial will allow that user to change how controlled or, on the flip side, how flamboyant his/her writing with the usual handwriting technique and amount of applied pressure will look on the page, and alternatively, how much effort it takes to achieve a particular "flair" or look. There are days when I feel more energetic and purposeful, and others on which I would be less so; the softness control can be used to "make it up" for me, when I don't feel like using as much force and concentration, so that my "personal" writing does not come out looking flat on those less energetic days.
The nib is very responsive to changes in the pressure applied, in the sense of rapid "snap-back", even at the maximum-softness setting. None of this "wet noodle" garbage that stops the tails of minuscule 'g' and 'y' in English, as well as the tí, wān, piě, nà and gōu strokes in Chinese kǎishū, from ending with crisp, sharp points that make the proper aesthetic.
The other thing that the dial does, as @TheDutchGuy has pointed out earlier, is noticeably change the apparently wetness of the pen. This would be very useful, either to accommodate different inks of which the user likes the colour but not the flow characteristics, or for ink reviews. If I was still of a mind to do detailed ink reviews, the Pilot Justus 95 would be a marvellous writing instrument with which to demonstrate how the ink would appear coming out of pens of different levels of "wetness" — not that I think the Justus 95 deserves to be relegated to fulfilling only a primary role of test equipment.
Before I received my pen, I was a little apprehensive that EF wasn't a nib width option on offer; but the F nib has proven to be quite fine enough for my purposes. More importantly, irrespective of the softness setting it can deliver almost equally fine lines (when little or no pressure is applied); the difference is in the "wetness" of the lines. While that isn't nearly enough to make it a "grail pen" for me, I've long been yearning for a pen that will deliver crisp and narrow enough lines (at least to be worthy of a EF or F nib width grade) but "wetly". This pen will certainly do it, if any pen can, at the maximum-softness setting; but if an ink proves too "wet" for a particular application or a particular type of paper being used, that dial may just be the trick to make that ink usable on that paper.
Is the Pilot Justus 95 worth the price I paid for it? I certainly feel that way. Was it worth the wait? Given that the long wait should've been entirely avoidable, I don't think that's a reasonable question; but I'm glad I didn't cancel the order out of impatience. (One of the other factors is that Japanese sellers seem not be able to offer the models with the barleycorn guilloche pattern, but only ones with the length-wise parallel lines, which is a style I don't particularly like.)
† With other readers in mind, I have marked out these points of difference from the O.P.'s pen that is reviewed.