Ok, to get back to the question...

Stay away from Intercontinental, it's old and in a bad area.
At ~200usd Alvear Art (part of the Alvear trio), is a great value for the money, the rooms are high quality and the Spa/pool area at the top floor is marvelous. This is a great hotel, the price is mainly because the location is not that great.
For ~300usd, Alvear Icon, is the newest member in the family, and the newest luxury hotel in BA. Higher quality than Alvear Art and located in Puerto Madero. The top floor bar/restaurant has one of the best views of the city.

Again, the "blue dollar" and being regularly mentioned as one of the best PH in the world, makes Palacio Duhau an opportunity not to be missed for anyone coming to BA and looking for a luxury hotel. Not to mention that if OP is a Hyatt Globalist, a suite upgrade is pretty much guaranteed.