Interesting. I thought the Pace was superior in flavor even to the Pantin. The flavor of the pace is astounding; it has a sweet caramel flavor. Pablo Lara named the Pace after himself and his wife; the Pa are his first two initials and the Ce are the first two initials of his wife.
The Lara family is to mamey as the Zill family is to mangoes. They are the premier mamey grower here in South Florida. It's hard to ignore the recommendations of Pablo and Julian Lara.
The comment that Julian Lara made about the Viejo is that the flavor is variable. Some years it's sweet and others it's not. There was an FSHS article where the Viejo had the lowest brix of the cultivars tested for one year in particular. Seeing as how this winter was the warmest in umpteen years with only a dozen chill hours, it's likely that this year's Viejo crop was much sweeter than normal.
In addition to the astounding flavor of the pace, it bears outside of mango season. This is significant to me, since during mango season, lots of other fruits tend to rot because there is simply too much fruit for one family to eat in that two month period :-). So, I tend to seek after fruits that bear during other parts of the year.
Precocity is another significant factor here. I have a pantin that's now been in the ground for 6 years and looks to be setting its very first crop, which will be ready 12 months from now. With excellent soil, there's the possibility of getting a crop in a shorter period of time. But in general, it's not known to be quick to bear. The pace is said to be so precocious that it sometimes starts setting fruit in 7 gallon containers (~2 years old).
IFAS has a great article
comparing the various cultivars and their attributes.