2.6 jr. or 3.0. ?
You should be more specific. What frame do you have, what situations do you plan to use the tire for, etc.
As somebody who is not too experienced yet, I can’t give you a lot of advice. I hear from others that the 2.6" gazz is a better all-around tire because its lighter, still can handle the tough off-road stuff, but is better for street stuff.
I can tell you that the 3.0" is a monster, and is heavy, but I love it. I wish I had a chance to ride off-road more. One day. For now, I use a street cycle with a street tire.