Ask the Expert or go to GORP's Climbing Forum to exchange information on climbing destinations, partners and much more. Try GORP Travel - Climbing for climbing trips and schools. Harnesses weigh anywhere from two thirds of a pound to a whopping two pounds. Lighter is better, but don't compromise comfort for a few ounces. The features you need in a harness depend on what type of climbing you will be pursuing.
Standard features are a belay loop, a haul loop, padding, and reinforced gear slings.
You might save a few dollars buying a stripped down sport rig with limited racking capabilities, but both use and comfort will be limited. The ability to micro-adjust a harness, depending on what you are climbing, and what your are wearing, is extremely handy. While all harness buckles are built to endure the most rigorous of testing, they are not all equal. Most are of the double back variety, but they vary in the effort it takes to thread the webbing. All you need to do is snug them up around your waist.