I like my SAA-2N, it is the one I generally reach for in the shack. It works fine with external programs or standalone, updates work fine, and I like the type N connectors, as my shack is mostly type N. The provided cables and calibration standards appear to be of high quality and performance. Got mine from R&L. Highly recommended and I have been using VNAs since the '70s and am pretty picky about instruments.
73, Don N2VGU
Donald S Brant Jr