The 686 has a crisp break like glass single action with no take up, due to the very small engagement surface between sear and hammer notch. The ruger has a much larger engagement surface. As I pull the trigger, I can feel the sear drag across the hammer notch.
In double action, the 686 is smooth and consistent. The ruger is gritty and has hitches throughout the travel. The grittiness can be taken care of by a good trigger job. I have felt much smoother ruger triggers than mine.
What can't be fixed is the inconsistent pull in the ruger trigger. One of the sources of friction in the trigger is the rotation of the cylinder. On the 686, the cylinder turns at a constant speed from start to finish, and locks up just before the hammer falls.
The ruger cylinder rotation isn't constant.it changes throughout the trigger travel, and locks up well before the hammer falls. It makes the trigger feel like it has hitches.
Lightness does not make a good trigger. I tried light springs in my ruger. It still feels gritty and jerky, but now with the bonus of not reliably firing.
If smooth and consistent, heavy is ok.