Every company can have a lemon now and then. In my 20+ years DJing I could tell you some stories about CDJs and their biggest failures that Pioneer do not want you to know 😉
Now for the SB2 and Platinum: Both controllers are about on par in terms of build quality, as both Pioneer and Numark have those models made in China, but in a good factory. Now it all depends on which layout you prefer as they can do pretty much nearly the same.
So actually I would get high-res pics of the controllers and look which one is more appealing to you. The Serato integration is excellent with both and it is small things like the displays in the jogs on one side and effects cross on the other that make little differences.
So we cannot give you a definitive suggestion here from the staff, but you cannot go horribly wrong either way. They are both good controllers and will get the job done even in harsh live environments.
