What is faster Asynchronous SAN Replication or Asynchronous AAG?
Let me make one thing clear before we go any further.


  ... SAN Replication or AAG, i.e. block-level or transaction-level


AlwaysOn Availability Groups do not work at the transaction level. The unit of work is at the log block level. This is very different as we ship log blocks for all transactions, whether they are committed or not.

The most likely "fastest" shipping mechanism would be the SAN replication given the parameters set forth and given the current versions of SQL Server generally available. This is only taking into account the literal question of "what method makes my data get to the other end the in the least amount of time?".