Mike your answer is way to general. You cannot make assumptions unless you live have direct experience in a particular area. In my neck of the woods, in some neighborhoods well over 50% of the homes may have sump pumps. The answer to this question depends on many things:
- Is it customary for homes in the area to be built with sump pumps installed (in some areas this is true)?
- Is there a flooding problem in the area or this house in particular?
- Does this house have a history of flooding or water damage?
In my area, as long as you explain why the sump pump is there and if any water regularly comes into the basement, it should not affect the sale of the home.