Sedo recommends that Buy Now with a fixed price is the best way to sell a domain. In fact all sales veues recommend this approach. I personally don't heed this advice because I sell the same domain at more than 1 platform, and I don't want to be caught out selling the same domain to 2 people at 2 different sales venues. Yes it can happen, but it's rare. I list all my domains for sale at Sedo, Afternic, GoDaddy, My own website, and from links from parking pages. My most successful venue from these 5 is selling at GoDaddy. It just must be about the number of eyeballs.