A DJ friend asked me which DJ software I liked the most. He had narrowed his choices down to Serato and Traktor. After explaining to him that I was extremely biased, having used Serato for several years, I told him my weapon of choice was Serato.
I currently have both Serato and Traktor. After doing gigs with both programs, I find that Serato is more intuitive and cost effective for the working DJ.