I agree with Henry and lawnboy. I have their power roller but haven't used it yet cause it looks like it will take more time to clean than it is worth to paint one room. I don't like painting but I plan to try it in a month on a room and will post back with the results.
I have tried their sprayer and even a regular air gun and they just don't have the oomph to spray latex paint cause it is too thick. It is too much trouble to thin it and use their funnels, etc. The sprayer is a pain to clean. I would love to own an airless sprayer but don't paint enough to justify it.
Good luck. I am impressed with lawnboy painting 8 rooms in a hour and a half and would appreciate some tips from him on how he does it. Specifically I wonder how he cuts in the corners, next to baseboard, and next to popcorn ceilings. When I try to cut in with a brush, you can tell the difference between the brush stroke and the roller stroke.