It depends on the market.
We just did the math in our office last week, and there is currently only 4 months of inventory in Miami at the moment, therefore, it is a Seller's Market down here due to the influx of cash from Europe and Latin America.
Why would anyone offer a bonus, when every seller and landlord is getting bombarded with offers? I had a seller's agent who recently announced that they would only show the property to the buyers who were willing to offer above appraisal. Needless to say, my buyer passed on that one (and there could have been a $10,000 bonus on it, and it wouldn't have mattered), but there were plenty of others who jumped in, and with cash!
In a Buyer's market? Not sure. It could, in the very least, get you into the "showing list" more often.
Investors, on the other hand, are a whole other story, usually unaffected by the ups and downs of the market, and looking at the properties from a detached perspective. Most of them depend on their agent's judgement, and some literally buy just from the agent's recommendations and a few online pictures.
In this situation, if the property with the bonus is a good investment and is well priced, an investor's agent might be more likely to recommend the property in question vs. another similar property, as long as the cap rates make sense.
Hope that helps!
Gloria Rodriguez de los Reyes
(305) 229-1146 Office
(786) 322-9438 Cell