Sheer Blonde Highlight Activating Volumising Shampoo (I use the honey/caramel version) is a fabulous product. It leaves my hair feeling soft and smooth and it takes longer to get greasy again compared to other shampoos I've used.
It really lives up to its claims. After using, my hair looks shinier and reflects light. My natural highlights are more obvious, and overall my hair looks fairer. It also works well as a volumising shampoo.
Since I started using the shampoo, people have commented on how my hair looks shiny and like its getting blonder (naturally a dark blonde). The only downside is that the shine does seem to 'wear off' slightly - so if you wash your hair in the evening, it won't be as shiny the next day as it would be if you washed it that morning. However, the effect is still nice.
Overall, I really can't think of any negative points. Some people might be put off by the price, but in my opinion it is well worth it, and one bottle does last a reasonable length of time.