Our team has used 1" 80/20 every year we have been in existence (3 years). The ease of tapping and attaching items is really nice for us. However, I can see the argument that it is too heavy. Our robot (during build season) in 2011 was 40 lbs overweight at one point. Oops!
Last year, we did a much better job of weighing as we went and making a more efficient design.