How were Aztec priests different from the priests today- and discuss their role?

This is an interesting question. The main differences between Aztec Priests and Catholic Priests are threefold:

1. Wardrobe - Aztec Priests wore really cool hats with feathers and bones and stuff. Priests today wear robes. In both cases, however, the role of the special garments is the same - to emphasize the Priests' social status.

2. Chastity - Priests today are usually not allowed to have sex. Aztec Priests were under no such compulsion. This meant that, in Aztec society, they often increased the genetic diversity of the population by spreading their seed. In this way, they were similar to European village "studs".

3. Connection to war - Catholic Priests are imperialist stooges of the military-industrial-entertainment complex. Aztec Priests played a moderating role in foreign policy and often encouraged chieftains to restrain their bloodlust. Both types of priest were meant to speak truth to power, but the kind of truth was different based on culture.

That's all I can think of. The religious ceremonies are slightly different, too, I guess. But, when you think about it, is communion really that different from beheading someone and eating their heart?