I bought two balanced Z2Ks about two months ago from the SBF store. I kept one and sold one to my teammate. His broke quickly, probably less than 200 swings. Mine is still going strong and probably has 300 swings and no signs of distress as of yet. If you get any version of the USSSA Z2K,balanced or EL, with a QC3 or QC4 then you are rolling the dice. Personally I wouldn't buy one without a legit receipt.
The 2014 Z2K should be available for purchase within a month. The LS CSR is saying second week of June and they shouldn't have any durability issues according to LS.