What a pen! What a nib!!
I have about a dozen pens in my collection so far, in a range of mfrs and price points, and this is pen and nib rises right to the top of the bunch. The pen body itself, the Custom 912, fits my size 10 left hand perfectly. It is a bit longer and wider than the Pilot Custom Heritage 92, which I also own and love (MF nib on that). I personally like the flat cap top and barrel end design that this 912 and similar pens have over the classic torpedo end, but that has no bearing on how it writes or cradles in the hand. The length, taper, and diameter of the section grip is really perfect, and the cap threads on the body are minimal enough that they don't bother my left thumb as it rests on them.
The standout feature of this particular pen of course is the Waverly nib. I am a lefty underwriter, so my letter strokes push up and pull down for ascenders and descenders. The slight flair out of the nib puts more of the tipping material on the page, which produces a very, very smooth writing experience with a medium wetness. The lineweight is about equal to a European Fine, maybe a tad wider, but to my eye not as wide as a Euro Medium on Clairfontaine 90g paper in a Rhodia Webbie. It is perfect for my "normal" handwriting size. I've got it inked with J Herbin Vert de Gris and just love the combo.
If there is anything to gripe about it is the Con-70 converter. While it holds a reasonable amount of ink, 1.1 ml per the specs, and the plunger mechanism completely fills the reservoir, it isn't a tanker full and only slightly more than a standard full size cartridge. Disassembling this converter to clean out the ink that invariably winds up leaking behind the primary piston takes some effort and time, and there are many online videos describing the process. I am not put off by this, in fact I rather like the taking care of my toys, but for those who prefer a lower maintenance pen, it may be wise to stick with cartridges and put the converter in the drawer.