Less uses the ‘@’ symbol to declare variables. However ‘@’ already has meaning in CSS, as it is used to declare @media queries and @keyframes. This can result in some confusion when reading the code. Despite being similar to approaches like SASS, it’s adoption is far less universal, and therefore getting used to its intricacies may not be the best time spent if you’re not going to find it used in projects. Makes you rely entirely on mixins rather than allowing you to use functions that can return a value. Can result in slightly restricted use cases.