Just to close the loop. We did the MIA-EZE sector in Feb. Here are some comments if anyone is considering this as an option to SA.
MIA is undergoing a pretty major refurb at the moment and LAN are operating out of one the newer sections (I think this might be relatively recent move). Check-in was slow, with a number of LA/4M flights all scheduled to go around the same time. Fortunately, the Premium check-in wasn't too bad compared with the economy checkin.
LAN Business pax use the Delta lounge. Which is modern, but relatively small, but has showers and complimentary food/bar (which isn't always the norm in the US). But is is quite a hike to the departure gates. There is no direct airside connection to the American Terminal and Flagship Lounge / AC. But even if there was, they are even further away from the depature gates.
Unfortunately, the flight was about 2hrs late departing. More unfortunate that we realised after doing the hike from the lounge to gate. There was one suggestion that they had misplaced the plane... Anyway, it was not a huge issue for us, since we were due to arrive quite early anyway and had no onwards connection.
The 767s are the newer ER versions. The J cabin is 2x2x2 and quite pleasant and comfortable. The service was friendly and attentive. I must admit that the seats seem a little on the narrow side and the centre console gets in the way. I was unable to acheive the advertised fully horizontal position and there was a slight downhill slope to the lower end of the seat. Similar to QF Skybeds, I usually go for a slight kink in the seat to stop the feeling of sliding down!
Anyway, as an award flight, it was a pleasant flight (once up and away) and probably worth the extra 5000 miles compared with the AA J-offering. Mind you, that flight left on time and I could have used the Flagship lounge...
But if I was looking to do a status run closer to home, I'd happily do the LAN SYD-AKL run.