It's good just for the price! The one with the metal body, which is understandably more expensive, is by far much better!

Don't be fooled by the product's appearance, the parts are plastic, except for the tip.
In my XL version pen, the tip from the replacements got stuck at the exit. I turned the tip upside down and rotated it a little to "open" the pen's exit, and now it's okay without causing any issues to the pen.
But when you buy something that claims to fit all similar pens, especially a Parker with its reputation, you wouldn't expect to go through such procedures.

In terms of writing, it's okay. It's somewhat smoother than the classic 0.20€ BIC pens. Similar quality to its original ink.

I write a lot and it lasts barely 3 weeks, while a regular ink lasts 3 months. However, its writing is excellent like a roller, but without smudging.

Very good ink quality, naturally because it is gel it dries slightly slower than regular inks. Pleasant feeling when writing, as it does not require pressure on the paper, the ink flows smoothly.
The only negative is that sometimes the pen gets clogged and does not write, but if you scribble on a scrap piece of paper it fixes immediately.
I recommend it.

Updated: Thankfully it writes everywhere. It does smudge, but it writes. On wood, leather, laminate, aluminum, stainless steel, it is perfect for quick notes.

Very often it feels like it clogs and doesn't write smoothly. The line thins out and the color fades where you write. Parker disappoints me. I will try it on different paper and let you know.