I just did a round trip Miami-Santiago in Business. Flew out with American (777) and back with Latam (787).
Latam was in every aspects superior, especially for the service which is always "meh" to horrible on Americain Airlines. HOWEVER, as a 6"3 guy (1.90 m) the seat on Latam is way too short, there is no way to stretch my legs. I would say that this seat needs at least 8 more inches (20cm) to fit a guy like me. Needless to say that this short seat/bed made the sleep very inconvenient. The seat from in the American 777 is much "longer" but also narrower.
Bottom line is that you will be uncomfortable in Latam seat if you are taller than 1.70 cm. Below that, I would pick the Latam option any day (wider seat and better service). Unfortunately, as a tall guys, I will never fly again on Latam business.
I wish you could mention that in your reviews. Thanks for the good job anyway.