To my surprise the Jackson's paint seemed to live up to their claims. Pigment loading was good, lightfast ratings seemed good.
New tubes are marked with pigment types and you get a big 21 ml tube of paint for your money. They covered well. Flow was good, blending wet in wet seemed good and transparency was good. They didn't lift when glazed either.
By comparison the Holbeins seemed to work well until I tried glazing them. The under paint lifted and was difficult to correct.
The apples are Holbein on the left and Jackson's on the right. The difference is visible.
Another major plus is the price. You get a lot of paint for your money.