What makes a tyre good? In my opinion it is the constant development, which is the result of extensive research and testing. All good tyre manufacturers will invest a lot of money to test tyres to constantly try to develop better tyres. Safety, better wear and better grip tend to be the key goals. When it comes to winter tyres, the testing is even more critical and not everyone has the right facilities to do that.
Regardless of what tyre that you want to buy, you need to do your research to ensure that you get a good quality tyre. Tyre tests performed by car magazines tend to give you some indication of how well tyres perform in certain conditions.
Nowadays you have the EU tyre label that gives you the answers to three tyre related questions: rolling resistance, which translates into fuel efficiency, noise emission, which translates into the sound level and the wet grip which shows how good the tyre is when you brake.
A good tyres will have been built solidly and the tread design has been optimized for the challenges that you will face.