Elkaddict,
The only advantage to a 30mm tube vs. a 1" is the 30mm will allow for more windage and elevation adjustments. This maybe necessary if you are doing long range shooting out past a certain point. You can determine if a 30mm tube is need by looking at the amount of elevation that is need to shoot a particular distance based on your caliber of gun. Another expense in a 30mm tube is that internal parts are usually stronger, due to the larger diameter of the tube, making them tougher or more durable. The difference in brightness and clarity is basically due the quality of optics and the quality and number of lens coatings.
Jon Jackoviak
The Optic Zone
www.theopticzone.com
[email protected]