@chap > Yes the DDJ-ERGO can control Traktor Pro. It also comes with Virtual DJ LE, and can also control other versions of Traktor and Serato DJ Intro.
It's your own personal preference of what software you decide to use. There are lot of similarities between the software, but some provide you with different features that might be more suitable for your needs or style. You should download a demo version of each and see what you like best. :)