5 STAR? Why not. The pen is hefty, overbuilt, and designed to be used and maintained.
Writing is comfortable and nothing comes to mind, which means it is well designed.
The posting issue; not an issue. You don't want to post the heavy cap. The pen alone is sufficient.
Filling is a breeze; the piston smooth and the ink enters the chamber eagerly.
Writing . . . smooth and wet. In fact, so wet and broad a point that a rag paper is absolutely necessary.
This nib is not suitable to noodling on pulp! It is steel, not gold, platinum, or iridium, but is well finished. I
am not even tempted to pull out my Dremel felt wheel and compound . . . nicely done.
For those with a modicum of calligraphy skills, the pen can write with the Italic flourishes, but can be used
normally as well . . . both slow, determined strokes or a cursive writer with the ability to add a ribbon flair if desired.
I will buy the fine point pen for inferior paper . . . the 1.1 mm requires a quality pressed rag.
I have a finer Italic I fashioned on a Pelikan 120, and it handles cheap pulp notebook paper just fine . . . so the fine
nib is the way to go for casual writing on cheap paper.

My TWSBI Diamond 580 Fountain Pen has been continuously inked since it arrived. Diamine Violet looks gorgeous in it and is a good match for the ink flow. The 1.1mm stub is smooth and delivers a clean line. Fit and finish is better than expected for the price point. It's a very solid though not heavy pen. You can't go wrong with this one.

I'm an older fellow who cannot read his own handwriting so I'm relearning my penmanship with a self paced text on the italic style. I asked the local merchant to show me the TWSBI line but she had a different agenda. A lot of what makes something right is in how a person perceives the item-I like the look and feel of TWBSI fountain pens. I bought the other pen (it was less expensive and it works fine) but more often than not it's the TWBSI that I use. The fact that it works well MIGHT be just luck but I now own several of this make of pen and they all fill easily, write smoothly and feel good in my hand. As an online merchant JetPens is most definitely in the upper tier: easy to work-with, fast to fill an order and solid safe packaging with a trackable and swift delivery. I'll continue to order from them.

This is a pleasure to write with! It has just the right heft, the ink flows smoothly, the italic nib is exquisite. Bravo!

Nice sturdy pen. It's a joy to fill with your favorite ink. My only gripe would be it doesn't post, of course it wasn't meant to. One of these days I'm going to lose that cap. Nib is buttery smooth.