I've installed three of these - two 14" and one 10". First, let me say that the 14' variety puts out so much more light that I would not waste my time on a 10" again.
The brand I installed were these from Home Depot:
ODL, Inc. 14 In. Asphalt Flashing Tubular Skylight - EZ14SCANH at The Home Depot
I found it is important to carefully caulk the ceiling ring to the drywall to keep it from leaking cold air, but leave the lens ring free to remove for cleaning and inspection. I also insulated the outside of the tubes to prevent condensation. Tape the joints between tube sections carefully with the supplied aluminum tape.
Installation time was just a few hours each, doing it by myself on an existing roof. The clear plastic cap has a reflector built in and it is important to orient it correctly.
I love mine, as they completely transformed my dark second floor. I installed one over the sink in a smaller, dark bathroom and it provides natural light for the mirror which is reflected all around the room, making it a cheery space. I believe these might qualify for energy credits (less lighting needed).