What kind of issues ? I didn't go far but they shipped something that worked enough not to cause instant drama and be used by low level programmers for a while. I'm surprised but I'm not knowledgeable enough.
It was touted (or at least referred to?) as a "supercomputing" device, which it definitely wasn't, though I don't remember the numbers.
I find it kind of weird how many people were offended by our use of the term, supercomputing. The actual specs were on the front page of the kickstarter from day one. Not sure what people were expecting from a $100 SBC? Kind of interesting to note that the Parallella beat out the multi million dollar Thinking Machines of the 1990s in terms of performance...