Don't know the Palermo Tower property.... but I have various clients that are regulars at the Ceasar Park. They seem to treat regular guests very well, my clients that stay there have a surprising loyalty to the place. I gather its a decent option in its price/service class. Suggest you check over on Trip Advisor for the latest reviews.

Internet Speed in Argentina can be very variable, but compared to what you get in the US, Asia & Europe you will need to manage your expectations. I think its safe to sat that most 5 Star Hotels will have reasonable (again for EZE standards) speeds, but if you are going to be using specific applications that require very fast download speeds, you may not be able to get what you are looking for at all times.