Are prices overvalued in Buenos Aires? Short answer: perhaps, but not that much. Long answer: below is why.
Residential real estate prices are mainly affected by three variables: location, price and terms. Looking at prices in BA now, we can ignore the location part because that's very specific to where the unit is located. Lets analyse then price and terms. If you offer me very good terms, I don't mind paying more than market value. For example, suppose your want to sell me a property at 20% over market, but you offer me 40 years to pay it off and at a low interest rate. The terms maybe very appealing, so I will not mind paying the premium. However, if you offer no terms but want to be paid all cash, then I will expect a lower price. Cash is king: he who has the gold makes the rules (or something similar).
in BA, terms are all cash, so really there are no terms. Therefore, you can expect that in general, market prices tend to reflect the lack of terms, therefore, prices are at equilibrium or as low as you can expect. Thus, it is unlikely that if you wait, you'll get a huge discount.
If you are planning to flip a property, that is, buy cheap and sell high in two or three years, forget it. Sales commissions and other transaction costs are very high in BA, so that reduces the incentive to buy and sell and make a profit.
Who should buy? Only those with a long term perspective.
What does the current market offer, that it did not a year ago?Or, why is it attractive to buy today rather than last year? Large supply, which means you might be able to find exactly what you are looking for. Other times, inventory was low, so you might get stuck buying something you really did not love.
In sum, if you have a long term perspective, don't let the naysayers discourage you. Spend time looking, find a great property, and buy it. Don't worry about the price.