I bought a set of cups when I first began baking LC stuff, but I have to say that they frustrate the life out of me! The fact that a cup of something may vary so much depending on how packed it is and can impact quite a lot on some recipes is something I've found to my cost. Add to that the anomaly in terms of cup sizes (some are 250 ml size and others are 227 mls) means that you never know what size the recipe writer has used.
I really think that weighing the ingredients is the best method to ensure success and a consistent result every time. But I sympathise with those who are used to cups .....
Babs