Not sure which model DDJ you're talking about, but Pioneer generally has a really good reputation as top-tier hardware. However, I would say my experience is that the software is a bigger consideration than the controller, especially at the lower end when there aren't as many controls on the board and you have to rely more on the software. All Pioneer controllers come with Rekordbox, and the Numark MixTrack has VirtualDJ. I have limited experience with both, and I'd say that VirtualDJ is very beginner friendly but has a lot of limitations as you improve compared to Rekordbox. Personally, I've decided to use Serato and I'm very happy with it, but neither of those controllers support it. So between the two you mentioned, I would probably recommend the Pioneer DDJ. Also, welcome to the site! 🙂