I've a few Sailor fountain pens. Some cheap, some expensive. The ones I like are Sailor 1911 with Music Nib and the Sailor 1911 with Zoom Nib. The expensive ones are the ones with gold nibs, and those are the ones that also write smoother.
The main difference between the Professional Gear and the 1911 series is the shape of the pen. Professional Gear has flat top and bottom while the 1911 is torpedo shaped. Personally, I prefer 1911 for the shape but the Professional Gear does feel a bit more classy.
At the top of the cap is the Sailor logo. There are gold trimmings on the cap, bottom of the body and inside below the grip section.
This is a 21K Medium nib. It's really beautiful. I love the designs craved onto Sailor nibs. A portion of the nib is plated with Rhodium.
All the different parts of pens are interchangeable with the 1911 fountain pens. You can mix and match different parts. You can even replace the Sailor brush pen grip section for use with the Professional Gear body.
One nice attention to detail is the rubber ring between the grip and screw threads behind. You can screw on the body fast and it will slow down at the rubber part and you'll then turn it tight. It's like filling water into a cup fast and slowing down when it's getting full.
Below are some of my sketches with the pen.
This particular 21K Medium nib runs smoothly on paper and is a delight to draw with.
The lines are uniform and consistent as expected. Ink flow is good.
It's a beautiful pen and a great performer.
Do you need to get an expensive pen for drawing? Not really. It does however feel more satisfying to draw with a pen like this. It's one that I'll be using for a long time.