Hi there.
I posted at the beginning of the year about safety concerns. I had read comments on another website from people who all seemed to have been mugged in BA, which had alarmed me.
In the meantime, I have been there myself and have had such an enjoyable time. I would put Buenos Aires alongside Paris and New York on the list of cities a person shouldn't fail to visit in his/her lifetime. I am now a big fan.
It is true that one has to be streetwise and careful with one's belongings, but that is not so unusual in big cities. I got squirted at once in the vicinity of Avenida Belgrano and a US-American guy I met had been squirted at too, but nothing was taken in either case. Garments had to be cleaned, though.
To put it all in a nutshell: I plan to return to BA again some time in the future and - now that I am somewhat familiar with the context of the safety issue - security will not be something that will burden my mind. It is manageable.