We put a
solatube into an upstairs bathroom that wasn't as bright as we would have liked, and it has made a world of difference. As an added bonus, it lets in enough streetlight at night that I no longer use the lights when using the bathroom in the middle of the night.
I think total cost was like $600, to have a guy come out, cut a hole in our roof, install the thing, seal it up, and clean up his mess. Took him maybe two hours start to finish, including measuring and talking about what we wanted. He said he'd don't about 300 and hadn't had one leak yet.
We considered doing the install ourselves, for about half the cost, but quickly decided that it wasn't worth the lost weekend to figure it out, or the the risk of doing it wrong and making our roof leak.
We've been totally happy with it, even at the high cost. It makes a huge difference in your perception of a room. For the first month we had it, I kept thinking I had left the light on in there. I would totally pay an extra $5k for a $300k house with 5 of these thing in it.