I own the Sig IIs and have only heard the "plain" Sigs one time, several years ago, so I can't offer the comparison you're looking for. I can say, however, that the Sig IIs are very nearly as good as the 3A Sigs in a smaller, more affordable package. IMO, they are the best value in audio, delivering performance that, in many ways, approaches the best I've heard (a list that includes the Wilson W/P 7, Thiel 7.2, Revel Studio, and Avalon Eclipse). If you can afford the price difference, my suggestion is to go with the latest iteration.