Also, you cant call Puerto Madero and Palermo Soho "the same". One is a remote planned neighborhood of very expensive high rises, cut off from the city. The other is a classic old barrio, integrated into the city, with a very mixed population. My taxi driver I use for airport transfers lives in a very middle class apartment in Soho, and has for 20 years. He could never afford an apartment in Madero, nor would he want to. A lot of Soho, especially down by Cordoba, and up by Santa Fe, is extremely funky.
None of which is to put down San Telmo, which is actually too funky, authentic, and close to the autopista and La Boca to ever become anything like Soho.