Other North & South America Frequent Flyer Programs - Your experience with Aeromexico Plus?

I was looking for info on Aeromexico's Premier Class when I found out about Aeromexico's Plus program.

I would like to know if anyone has had any experience with the plus seats. If so, was it positive or negative? My flight is from JFK to CUN roundtrip. The plane on both trips is a 737-800.

Thanks!