Like most, I am not going to say that BA is safer, or less safe than City X, City Y or anywhere, one can only really judge by what happens to you, where you live etc., as has been reiterated....
One thing that I would like to say, I lived in Dublin, Ireland, for the last 6 years, and within 100 yards (or metres for those more accustomed) to my apartment, there were three murders in that time, (two with guns), numerous muggings (usally involving knifes which got used), and a fair amount of petty crime. Obviosuly I must have lived in a rough neighbourhood, or so you would think... I lived in the New Docklands area (on the South Side for those in the know), in truth, much like Puerto Madero here, and supposedly an upmarket area. Is Dublin unsafe? - No, of course not, but if you looked at the figures, you'd be surprised at how much crime there is, and yes, most of it is drug related, rather than poverty related, but it stills affects thos epeople who are murdered, robbed, mugged etc....
Point is, all cities can be dangerous, and BsAs is teh same. I live outside teh tourist areas, in Avellaneda, outside teh city boundaires, and so far, I have not been afraid to do anything, and do not feel threatened or otherwise - Maybe one day I will, and I will answer differently, but the advice (or advise) on here, about being sensible, are good, true everywhere, and if followed, reduce the risks.....
Come to BsAs, enjoy the lifestyle that has brought all of us that post on here to the place - We aren't making a huge daily exodus because teh place is terrible, so maybe, its not all bad.... I love it here.....