Once is the jewish community, Abasto is nearby. It's one of the more run down/dirty/dangerous sections of the city, especially at night.
Funny because in Sao Paulo the jews have all moved to the nicest/safest section of the city but I guess that just didn't happen in Argentina.
I do understand wanting to be near Once for shabbos, so if you don't mind switching hotels it's not a bad idea.
I would recommend buying Hyatt nights/points off someone.
Interesting you mention that, b/c if you ask some of the frum people who currently reside in SP, and are not rolling in dough, they'll tell you how they're $truggling to keep up.. Jardins is one of THE most expensive areas (think Rua Osacr Freire and Paulista), and yet for some odd reason, these large frum families are expected to live there(?!).
Imagine if the standard for the Frum family in NYC was to live on the upper east side!
Bom Retiro may be dangerous, but at least they can somewhat afford it (not even)..
I don't know if you spent some time at all talking to locals in BA, but the parnasa matzav there (from what i hear) keeps on getting worse and worse (living in "once" not withstanding!). People are struggling.. They really need lots of Tzedoko there, hope you contributed some
