Pros: Right smack in the middle of Palermo. Attentative staff -- had some internet connectivity issues (mostly it was just slow) and they upgraded the equipment in response to my request to fix it. Also managed to get myself locked out once and someone was there in five minutes to let me in. Nice unit, plenty of space for two people, and you could fit even more. Check in/out were smooth. Maid service once a week.
Cons: Right smack in the middle of Palermo, meaning it can be noisy. Keep in mind that Buenos Aires is a very noisy city, so you can't really avoid it, but this is on the second floor. That's basically all I can think of.
I would stay here again and was impressed with the attentiveness of my host. Highly recommend.