I haven't done much real work on the Adam S-3A's, but have heard them a few times. The studio I work at also has another location where there are some private rooms and one of them has these in them where I got the chance to hear some tracks played through them. Almost needless to say, I was pretty blown away by the full sound of these monitors, as the bass and mid range responsive is incredible while the highs are nice and tight. Unfortunately since I haven't used them for mixing or tracking it's hard to say how well they translate over to other systems.
The Adam S-3A's are perfect for a high end home studio or a professional studio, as they're simply an awesome sounding set of monitors. I've never heard a speaker from Adam that I didn't like, as I've got A7's at home. These are great for larger control room spaces where you might want more low end response if they're not going to be right up in your face. They're definitely not cheap, but if you're looking for a top end set of monitors, in general it's going to be expensive. I'm not sure that these would be my first choice for a set of monitors if I had a choice of any, but definitely keep them in the discussion.