Writing
I've touched on it a bit already, but I'll go into some more detail about the writing experience with this pen and nib.
The nib is super-fine, and makes a crisp, sharp line. I currently have it inked with Iroshizuku kon-peki, which works flawlessly on all the paper I own. I've never had problems with it being clogged, skipping, or drying after a few minutes of uncapped rest. The ink does tend to become extremely saturated and thick if left for more than a week in the pen. That being the case, it gets cleaned pretty often.
Apart from being scratchy, the nib does a beautiful job. It's firm and dependable. From the naked eye, it looks like the point has a small slant to it. This creates an italic effect on some papers. It probably wasn't designed this way, but I love it.
This is a great pen, but I don't use it as much as I would like because of the nib. Super-fine nibs are useful in certain situations (for me), but I prefer something like a fine or medium for most writing. If I can find one, I'd love to swap the nib out for an Esterbrook stub nib of some kind. I hear those are really difficult to acquire, but I'll keep my eyes open for one.
Overall
The SJ is a fantastic pen, and I'm so pleased that I bought it back in April. I went from knowing nearly nothing about Esterbrooks to becoming a fan of the brand and learning everything I can about them. It's so interesting to show people these pens and hear them talk about how they remember one that their parents used or that they personally used when they were young. These pens are a legacy, and it's really awesome to own and use a part of history. And, at the end of the day, it's still just a pen, and it does that job remarkably well.
(You can find more from Jeff online at Draft Evolution, Twitter, and App.net.)