The subject of a pre-listing (seller's) inspection comes up fairly frequently.
I think it depends on what part of the country you live in as to whether they are typically seen as an asset or not. Here in PA they are not frequently referred by Realtors. The objections I most frequently hear are that they can increase the seller's liability with respect to disclosing items. This can happen when a seller is made aware of issues they did not know about before and are not prepared to fix.
The second concern is that the buyer's inspector will uncover things the seller's inspector did not. This happens fairly frequently, many times because inspectors all have areas of expertise or strengths. The buyer's inspector may have been a master electrician and identify a few items that only his trained eye would catch. The seller can pay to repair several items believing his home to be perfect, and then be dismayed when more items are turned up by the buyer's inspector. This can leave a seller to wonder why they paid to fix those few items, or even why they paid the first inspector to begin with.
It can be a great marketing tool for sellers. It can, as many suggest, help prepare a seller for the buyer's inspection, and also help the sale price hold up. So, there are many advantages. But just to give a full picture, I thought I would share some cons, too.
Of course, as an inspector, I wish EVERY seller had a pre-listing inspection so I could be twice as busy!