I've worn Uniqlo shirts for a few years now and had no problem. However, it would seem that the quality has dropped enormously. I recently bought 5 shirts (priced at around £40 each). I've now worn a couple of them, and in one of the shirts the material split on both arms during its very first use. The material was not ripped. It just split (very weak rubbishy fabric). I contacted Uniqlo, provided all of the required information, pictures etc (3 times) and was eventually told that they were not prepared to offer any replacement or refund. What a disgusting company ..
