Thats really hard to answer because its unmaintained and SES, bounces and XenForo change. Just check the bugs and suggestions i filed here:
xenforo.com
Latest XenForo version fixes an important issue in the bounce handler. The SNS handler needs to be updated accordingly.
XenForo does not handle SES complaints. It seems julians addon also does not. IMHO this is critical.
@DragonByte Tech Mail does and is regularly pushing updates .
I think one of the most important things is to make sure that the solution you choose will keep working. If it stops working correctly without you noticing it, it can be a massive headache to resolve .
If you opt for both SNS and XenForo bounce processing then consider that this will duplicate the soft bounce count.
Id consider an actively maintained SES addon.