Originally Posted by Marambio

An 8-hour layover including changing airports means less than 5 hours at the hotel when you add check in times. I would just go to EZE and spend time at the lounge.

That said, the Holiday Inn off EZE might have day rates and they offer free transfer to EZE.

Originally Posted by Eastbay1K

Funny - you assume there's lounge access

But back on point - AEP arrival - figure a remote "gate" and by the time you go through immigration, get your bag, and customs, you will be leaving AEP approx. 1330. You can figure transit time of a bit under 60 minutes at that hour. If you leave the city after 1630 or so, plan additional time. If you are flying out in the main cabin of any airline, I suggest a 3 hour prior to departure EZE arrival (1750).

Note that if you are flying an airline that doesn't have a staffed ticket counter during the day, you will get to EZE with almost nowhere to go and nothing to do. If that is the case, I'd check out the HI near EZE. It isn't exactly airport convenient, but it is on the way and with a shuttle, you're in good shape.