I can only agree: when it comes to yarn, you absolutely have to pay attention to good quality! You’re saving in the wrong place if you don’t buy good quality. I also prefer using Catania; it’s simply wonderful to work with, it makes crafting really fun, and the finished crochet pieces look good for a long time. Or Limone by Schoeller & Stahl, which is just as good in quality as Catania. I once bought cheap yarn as a test, but as osaki already wrote, it’s dull and because of that it doesn’t glide nicely through your fingers, and working with it isn’t fun at all and is much more difficult. Mine has been sitting in the closet for ages now.
By the way: you can get both yarns (Catania and Limone) here at a great price, and the shipping costs are absolutely reasonable too
http://www.handarbeitswaren.de/