Bytargentina has provided very good service to me over the past few years
Their customer service is not like an USA company. I telephone repeatedly and end up getting good service. When I had a dishonest owner, BYT did the fighting for me. Reynolds is also a quality operation. These two companies act like they are in business for the long run.
Renting from Jackson or Barts or Argentine Rentals is really dealing with an American company. A higher level of service, but sometimes at a slightly higher price. You will not have non-working internet, except for an act of god. The apartment owners are really in control. You can only go with quality to avoid a dishonest owner. This is random luck with some of the agencies.