Carrots are great and have many benefits. The one big concern over carrots and beets too, is that they have a lot more Sugar available than many other vegetables.
I have voiced a concern on a few occasions about juicing excessively sweet. It makes me cringe to hear about some who juice carrots, beets, and then add apple juice or grape juice. Just more Sugar to feed the cancer.
Again, carrots are beneficial but don't forget the down sides such as Sugar content.