FWIW I had a Nexus 8 (I know, not an Alfine, but pretty similar) in my cargo bike; it never skipped a beat in 5 years with minimal maintenance, so I think some of the concerns are a bit overblown. I'd choose an A8 over an A11, but wouldn't worry overly otherwise.
Seems to depend on on where you live and the conditions you ride in. Here in Seattle, Nexus hubs typically do not have enough gear range for most cargo bikes and they reliably blow out within a couple years.
FWIW I had a Nexus 8 (I know, not an Alfine, but pretty similar) in my cargo bike; it never skipped a beat in 5 years with minimal maintenance, so I think some of the concerns are a bit overblown. I'd choose an A8 over an A11, but wouldn't worry overly otherwise.