Given the number of software analysis packages available to the MRS community, surprisingly little attention has been paid to comparing the performance of each, particularly with regard to multi-site and multi-vendor datasets. Standardization of MRS methods will necessarily require that processing and quantification tools also produce comparable outcomes. This abstract describes a comparison of five widely used software packages analyzing multi-site edited MRS data to quantify in vivo GABA+/Cr levels. The overall agreement between the packages was moderate, with packages showing systematic site-to-site biases. Further analysis on a larger cohort of data will aid in determining the cause of these discrepancies.