www. Buenosairestravelrent. Com
I used them during my 5 week stay in BA. Yeah I know the site is in english. They had someone who spoke fluent english meet me at the apartment (after I paid too much money for a remise from the airport, yeah I know) He went over the contract with me.
I was expecting to get hassled the day I left for my deposit money back. I didn't at all. I was pretty surprised. They were pretty cool about everything. Since they try to cater to americans I wonder that perhaps they actually don't try to dick everyone around. IMO their prices werent too bad. Seemed ok for me. I'm not representing them or anything, just giving my advice about a company that worked well for me (bc when I came I spoke NO spanish)
TM