I've had Ben Nye eyeshadow pans before and the reason I buy them is their quality. Excellent pigmentation, finely milled and easy to blend. Not excessively powdery, but they perform better when applied with a quality brush and a light hand - you can always layer on more if needed, as they do stick precisely where you put them. The longevity is indeed professional next level. Also, no oxidation. I recommend using a good primer though.
Top points to Ben Nye for probably the best all-round colour range. They have an excellent selection of true neutrals in different shades so it's easy to build an all-occasion palette that has nothing extra. And considering the price of a pan versus the amount of product you get, well, getting something extra to the palette isn't such a bad thing either.