We like to think that VELUX Sun Tunnels are the best tubular skylights on the market. They offer a 20 year warranty on their reflective coating, which is a process other off-brand units have trouble replicating.
Beware of cheaper units as they often have trouble keeping the shiny interior of the ducts from crazing or separating from the metal over time.
And others claims concerning a percent of light transfer are difficult to verify. Houseworks does not recommend the flexible tubing or duct…it just doesn’t provide the light that the rigid product does.