IIRC the TL;DR is that the A8 is mostly found to be more durable/reliable than the A11, and that in grotty UK weather conditions, both may well benefit from better lubrication than the factory setup provides.
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.
There was a lot of discussion about this on the CTC forums; there's a lot out there if you search, but there's this monster thread in particular: https://forum.cyclinguk.org/viewtopic.php?f=5&t=64432
IIRC the TL;DR is that the A8 is mostly found to be more durable/reliable than the A11, and that in grotty UK weather conditions, both may well benefit from better lubrication than the factory setup provides.