What are the main factors that define what a quality design of a system is?

What do you cons开发者_StackOverflow中文版ider to be the main factors in a quality design of a system?

Following the GRASP Patterns (low coupling / high cohesion, protected variations, etc). What more?

Bob Martin's SOLID is what I'd recommend.

Probably, you could also look into:

DRY, YAGINI, Rigidity, Fragility, Viscosity, Immobility.

You can refer here for explanation of some of them.