This is an amazing pen - in a number of ways. It is such a fine instrument that I rarely take it out with me as the pen in my pocket. Don't get the wrong impression, it isn't fragile. I just admire it so much that I hate the thought of it getting lost or damaged. It is very well made.
STYLE. I'd rather not begin with a negative but the color of the pen is not my preference. And my commentary on style preference is not much help unless we have the same taste. But here it is: I like the classic cigar shape. I just don't care much for gold and brown (amber) anything - that's one of my least favorite color combos. Yes, I know that there's a smoke and chrome version but I couldn't find that one at a price I could afford. Now that I know how much I love this pen, I should've waited until I could get the smoke grey version. However, the brown translucent body looks better with ink in it. Especially blue ink, which cools down the warm color.
The size of the nib in comparison to the rest of the pen is right by my standards. A large pen with a small nib looks awkward; like a 6' 4" man with size 7 shoes. The large nib looks great on this pen. A secondary style issue is the way the pen is presented to you: It comes in this huge satin lined box with a large 70ml bottle of Pilot Blue ink. Now that's style! And, the ink is a rich color of intense blue that flows smoothly without bleeding.
CONSTRUCTION. Construction quality is excellent. It is made in Japan. The 823 is more complex than most fountain pens - more so than even a piston filler. The gold banding has nice detail. There are no rough spots, burrs; nothing is out of place or misaligned. It is perfect. Capped: 5 7/8". Posted: 6 3/8". Without cap: 5 1/8". Diameter: 1/2" (body), 5/8" (cap).
CAP - CLIP. I like the classic ball clip. It holds tightly to my shirt pocket without feeling like it is going to rip the cloth when I pull it out. Threading is nice and smooth, and the cap mounts deeply and securely to the end when posted. Nice details on the cap band tell you that it is a "CUSTOM 823 * * * Pilot Made in Japan"
FILL. The 823 holds an enormous amount of ink, and since I have a fine nib I have not filled it in quite awhile. So, it is difficult to describe well how this filling system works. It is not a piston filler; it is a vacuum filler. Additionally, you can close off the feed so that it wont leak when you are flying. The end cap operates the plunger and also opens and closes the reservoir. This is odd until you get used to it. If you forget, you'll find yourself running out of ink and wondering why. The end cap must be turned a couple of times to open the reservoir. When you're done just dial the end cap back down and you're safe from accidents. I have only used Pilot ink in it and have never had any skipping, drying, or even priming starts - it always writes.
NIB. As if the filling mechanism wasn't enough to commend this great pen, the nib is just as phenomenal. It is a large 14ct gold nib and was perfectly tuned out of the box. Mine is a fine nib and is smooth and friction free. I like a little bit of tooth to help me stay on track but this pen has no feedback at all. That's no complaint though, I respect the fact that Pilot can create such smooth free-flowing fine point nib. It writes effortlessly and is my first choice for long periods of continued writing. Besides, I have plenty of other pens that can give me feedback when I want it.