Kashi is a brand that has a range of cereals with different nutritional profiles. Which is "better" depends on your nutritional goals. There are some Kashi cereals that have just about as much fiber as All-Bran, and more protein to boot.
You can go to
www.kashi.com and see the nutritional info for all of them, and then compare that to All-Bran.
As with any food, it's all about what YOUR goals and personal guidelines are. Any of these are perfectly healthy choices, which is the best for you is your choice.