Testing of 20 × 20 × 15 mm3 3D position sensitive, CdZnTe detectors grown by Redlen Technologies Inc. has shown that 98 out of the 145 detectors analyzed achieved sub-1% FWHM at 662 keV for single-pixel events. Improvements in the detector performance over time reflect the improvements in detector growth and fabrication over the past several years. In addition to the spectroscopic performance of the detectors, the imaging performance of each detector was also quantified. The results show that imaging is weakly correlated to the spectroscopic performance, and more strongly correlated to the accuracy of the depth reconstruction. Other detector issues such as gain deficit and gain variation are also discussed.