The fan is a remote, in-line fan. It is hard to tell it is running unless you're listening for it. In my case, the fan is about 6' from the room in the duct, but it would depend on the length of your ductwork, and where in the line you chose to install it - mine is near the end of the run, fed with insulated flexible duct. I chose to install it there, since it is rigid and then it hooks directly to the roof cap. This supports it well and puts it as far from the room as possible. But, even in the attic, it's hard to tell it is running.
They've added a bunch of options to their line since I bought mine and the grill in the bathroom when using the fan is quite different. One neat addition is the light damper, which would make use in say a bedroom nicer if you wanted to sleep in. Otherwise, it would get very bright when the sun came up! They'd be nice in a closet, too, since the color temp is good and it blocks nearly all UV. Should make selecting dark blue/black eaiser!
The company started in Austrailia where underground, hillside houses are more common (to avoid the heat). The light pipe can bring in a huge amount of light with little loss. As you can tell, I'm sold on them. The copy-cats' light efficiency and color temperature tend to be worse, but maybe easier to install. For example, there's one company whose light pipe is corrigated and flexible rather than rigid - it doesn't bring in nearly as much light. Most don't coat their light pipe as well, and the color temp tends towards the blue end, giving things a weird color, sort of like some of the older florescent lights. Solatube's is very close to a good mirror, and transmits most of the light spectrum. It comes with protective, peel-off plastic film, and needs to be protected prior to installation. It seems pretty robust, as mine still looks new after over 10-years.