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Generally, you want to use the option that corresponds to which attribute or attributes are most likely to be be different across different flows egressing out the Etherchannel.
For example if you had a router gateway IP supporting many other subnet hosts, often from traffic going to/from off the subnet would have the gateway's MAC and a host MAC. So for traffic going from gateway to host, you might want to use dst-mac or src-dst-mac. For traffic going from host to gateway, you might want to use src-mac or src-dst-mac.
In addition to what attribute or attributes are likly to be different, you might want to account for traffic volume. Assume one host is really, really busy and has 90% of the traffic going off the local subnet. Instead of using for traffic from host to gateway src-mac or src-dst-mac, you might want to use dst-ip or src-dst-ip. The converse choice might be src-ip or src-dst-ip.
As you might have noticed, the combined attribute choices, e.g. src-dst-ip, allow the same choice in both directions because generally part of the selected attribute is changing regradless of traffic direction.
