Doing a little searching, I found a couple sound bites...

• According to the National Association of Realtor’s 2013 Profile of Home Buyers and Sellers, the average FSBO sales price was $174,900, while the average price for a home represented by an agent was $215,000, a difference of $40,100

• Not only do FSBO's empirically take longer to sell, 20% of them end up relisting on MLS which converts to an average of 68 days longer on the market than realtor properties.

If they are selling on average 68 days sooner and for 19% more money than an average FSBO, that's a pretty compelling argument.

source 1 source 2

FSBO sites response to those results include... * $150,000 - the average selling price for FSBO homes in 2011. Real estate agents like to tout their average $215,000 selling price over the same period, but the numbers skew higher for agented sales due to high-end sellers' preference for using agents and the fact that agent sales have commissions factored into the selling price.

I can buy into the skewed data a bit, although FSBO doesn't offer any insight into how much that skews data and what results might look like without the skew. I’m concerned that they don’t exactly say realtors aren’t still selling the houses quicker and for more money.

agent sales have commissions factored into the selling price.

If they jack up the selling price by $10k to account for the commission, and someone pays it, then that was a wise move by the realtor.

• The #1 reason a house doesn't sell quickly is incorrect pricing. You need to know what your property is worth so you don't overprice it or, worse yet, sell yourself short.

The above point from FSBO is huge, and I don't necessarily think this is easy to do as it may seem when you get down to it. Houses are filled with different features/levels of upgrades, size, ages, and it could be somewhat difficult to pin point a sweet spot for price.

FSBO Source

While users on here have success selling a home on their own, it leads me to believe it's not nearly as easy as some people make it sound.

From reading the comments, it makes me think “why do realtors even exist?”. Doing some quick desktop research shows that while it’s not necessarily hard to sell your house on your own, it’s really not that easy to do it quicker and for more money than a realtor can. I have to think that the more time I spend in my home, the more I keep making mortgage payments. If you have a buyer lined up already, the choice seems obvious. However if you don’t, it’s not that obvious.