Fruit is one of those contentious foods in the world of Paleo. Some people like to eat them every day while others insist that fruit should remain an occasional treat due to its high carbohydrate content. The argument really boils down to what works best for you. Some people prefer to severely restrict their carbohydrates while others find that they feel better with a slightly higher carbohydrate content, in which case, fruit can be an excellent, healthy way to get those carbs.
Berries are a particularly wise choice for those who choose to indulge. They are low in sugar and high in antioxidants and nutrients like potassium and calcium. Eating them by the bushel is still not recommended, but a handful here and there can be beneficial.
Mark Sisson has a blog post where he gives his take on the benefits of eating berries.