It looks like all of the answers are from Real Estate Pros, so as an individual seller, I'll share my opinion. I just recently listed with C21 Clickit. There was an error on my listing, but it was minor, I called and they corrected it immediately. I agree with everyone elses assessment that selling on your own is a lot of work. However, I found myself doing a lot of that when I had a realtor list my house. I heard every excuse as to why they would not do open houses, but none (I had three) could tell me what works. The other advice I commonly heard is price sells a house. Coincidentally, don't realtors always say what matter is location, location, location? Okay so, make up your mind, folks! None of us can change the locations of our properties, so now what? But, I digress. My house is only three years old and is in competition with a builder that has been changing alleged starting prices at an alarming rate in the past three months. (3 months ago they were starting in the 180s, then went up to 220s, now down to 170s - crazy!)
Again, I agree that FSBO, regardless of the site you use, is work for the buyer. I think the key is to be organized, have a marketing plan and budget established before you begin, read everything and find a real estate attorney you can trust to handle the transaction. Don't expect any flat-fee/FSBO site will do any more than what they say. Good luck and prayers for a quick sale go out to you!