I know an estadounidense who imported a Lincoln Town Car from the States, is completely licensed and ensured to be a remis driver here in Buenos Aires, maintains the car impeccably (very difficult because they don't make parts for it here) and his door-to-door service only costs $65 dollars.
Yeah, $170 pesos or so ($45 USD) to/from the airport is a big rip off.
You can grab a remis there at the airport (if they have a ride available) for cheaper than that.
Don't go with guys who are coming up to you and asking you if you want a ride into town. Most of the time they are hustling, although sometimes there is someone actually from a cab stand that is looking to get people rides. If that's the case, they will take you to the cab stand and you will get a ticket and go in a cab, all above-board. I don't know what the official cost is nowadays for sure FROM the airport, but it's around (maybe less?) $100 pesos.
You can often get a cab here in the city to take you to the airport right off the street for the price of the meter, which is less than the "offical fare."