i don't know details but do a lot of homework and remember that Performance and Nashbar are owned by the same company and that a huge portion of their business is buying closeout items as opposed to just stocking latest and greatest items. It's possible that if BOTH of those wheelsets had a history of issues the manufacturers closed out remaining stock and hence cheap prices at peformance.

I can tell you that the ea 90 SL (not the slx) has a really bad history of spoke breakage despite the fact they appear to be a stronger wheelset with 24/28 spokes. you may want to seek new wheels elsewhere and save your performance discounts for something else