I knit with wool Opal since now more than 30 years and for about 20 years.
Convinced the quality and also justifies the slightly more expensive price. This is worthwhile, however, if you take considering how long you sit up a par sock is ready knitted. Because they should be managed to hold for a little while and not go immediately broke like so many cheap want.
+ Opal - Quality
+ Washable
+ Great colors (color quality)
+ Do not wash out
+ Will wash through not hard
Very comfortable to wear +
+ Run when knitting easily through your fingers
- High price