UA or Copa to EZE

I have a NYC-EZE trip coming up. Options are:

Copa recliner JFK-PTY-EZE-PTY-JFK

OR

UA lie flat LGA-IAH-EZE, and use my own GPU to waitlist EZE-EWR (now RN=0).

Seat... lie flat is night and day comparing to recliner on 11 hour flight, but I am taking a risk of E+ on the way back, plus using one extra GPU

EQM... 16539 on Copa vs. 15007 on UA

What would you pick?