Based on flavor of the varieties I have tried, here is my ranking:
1) Lorito
2) Green Sapote - TREC (close enough to mamey)
3) Pace
4) Pantin (may not have tasted a prime example)
5) Viejo
6) Magana
Sepeda(Cepeda?) Especial is rumored to be excellent.
I have 7 trees in my yard in the ground over 4 years, pantin, pace, lorito, Viejo, Sepeda Especial, and TREC GS. I have only harvested 3 pantin fruit. Lorito has the nicest appearance and is the best grower. Pace and TREC are the slowest. Next year, I will probably harvest around 30 fruit.
I have a Pace tree that was planted as small 3 gallon tree in October of 2011, while my Pantin was planted as a 7 gallon tree in November of 2012 and my Viejo as a 3 gallon tree in 2014. None of them have provided any fruit. The Pace has technically fruited, but it popped off all of it's fruit. My Pantin is actually more vigorous and larger than my Pace. The Viejo, which is the youngest, has set three fruit this season and now has only one that is the size of a golf ball and seems to have a more spreading growth habit. I took some pics today.
Pantin:


Pace:

Viejo:

Viejo fruit protected by three organza bags. lol
