Noise reduction is touted as the best attribute but isn't this down to glass pane thickness and spacing? So, is a triple glazed install better than double glazing?
Triple glazing is usually touted as the best for energy reasons.
Your best comparison, insulation-wise, is to compare the R-value / U-factor of 2 units. The U factor is nothing more than the reciprocal of the R value. A window with a R 10 rating will be a U 0.10 (a great window currently.
Triple glazing is the darling of superinsulated homes and has a price to match. They typically only make sense in colder climates where heating costs would justify the expense. Windows must be paired other areas of energy conservation: air sealing, ceiling insulation. An energy audit that does a blower door test, paired with a thermo imaging analysis, should be done before upgrading to triple glazing. Some local utilities have discounted energy audits.