We love the skylight, plenty of natural daylight. We prefer natural daylight as opposed to lights when at all possible.
In terms of the heat, there are VERY simple solutions for when its hot and you prefer the darker and cooler camper. We have a strip of Reflectix insulation that blocks out 95% of the light, then a piece of foam that we push into the skylight from the inside. That does at least as good a job of insulating the skylight as the factory insulation would have done.
That gives us the best of both worlds... natural daylight when we want it, effective insulation when we don't.