Today I prefer the Pilot G-2 0.7mm. The construction is plastic but decent quality for a disposable pen. The clicker and screw joint have excellent fidget properties. The ergonomics are good except for the injection nub on the rubber grip, and the ink is the best I've found in a cheap disposable today.

In the 1980's I preferred Uniball pens. Back then they had unreasonably high construction quality for a disposable pen with precision fitting parts and a stainless steel clip. The roller and ink were also very high end for a disposable of the time. Unfortunately it doesn't look like they build them like that anymore.