A 'good' pilot is one who flies smoothly and in balance - so much so that you wonder whether you ever can induce them to do something roughly.
Things which stand out are using elevator as they smoothly and slowly feed in power on gravel. Or, when slowing in the circuit, the nose rises as the power reduces, the altimeter stays glued, and as the IAS drops below white arc, they feed in flap so that there's no need for trim change, and so, no frightening pitch change, and less grunting and twirling bloody trim wheels.
When given a go-round from low level - they feed in the power without the donk coughing and shaking, at the same time getting the nose up and flap bled off to climb setting - all without screaming stall warning horns or frightening attitude changes.
Good pilots are situationally aware. They know where to look for traffic, where to look for windsocks, pick up the cues for windshear etc. And they don't do it with much fanfare and consulting of check lists! It just fits in with the flight sequence.
Good pilots have thought about the order of things, and get themselves planned for each phase of flight that's coming up.
I don't think it matters whether it's a 150, or a 310, or bigger - some will always be 'better' pilots than their peers, because they give confidence to instructor and pax alike.
There are some PPL's about who I'd rather be flying with than some of the CPL's and Instr 3's who pass through - hours, theory passes ,and procedural excellence have damn all to do with what makes a 'good' pilot.
cheers,