Perfect for note taking - uni Alpha Gel pen with Pentel Energel refills
https://www.amazon.com/dp/B00O4P5CI2/
That would be my recommendation in the <$20 price range.
Edit: for ergonomics, I'd suggest this one https://www.amazon.com/dp/B001BYNGGO
IMO there is not much difference between the Schmidt 888 rollerball refill and the Pentel Energel gel refill. In fact I changed the Lamy Rollerball refill to a Pentel Energel refill in this pen.
So here are a couple of suggestions: uni Alpha-Gel with the Pentel Energel needle-point 0.5mm refill - also available in 0.3mm and 0.4mm
You can also use the same refills in the Dr. Grip Limited Gel Pen.
The 0.3 and 0.4mm are available in red and blue ink, the 0.5mm refill is available in more colors.
If you are going to be writing on satin or glossy paper, the go with the 0.3mm Staedtler Triplus Fineliner which comes in many colors, including black.
If want to change pens, I would change refills also. IMO the Schmidt EasyFlow 9000 writes smoother and blacker than the Jetstream and it is cheaper if you use the Jetstream refill for Parker compatible pens.
Suggestion: Rotring 600 - price runs all over the place on Amazon but you should be able to get one for <$25 if you use CamelCamelCamel - this is my go to everyday pen.
A different option is the uni Alpha Gel with a Pentel Energel refill - this is a favorite among many.
You could always take a look at Smootherpro - they have pens that take Parker G2 and Pentel Energel/Pilot G2 refills
