Unfortunately, I also can find not one good review of the Sturmey Archer 8s.
nobody who has them seems to be happy with them... Most reporting problems with them drifting out of gear, and consequently tearing up internally.
i am finding reports of them breaking after 120 miles and less, and these are all reports of folks just pedaling... No electric motor users.

if you get the Sturmey, please be sure to post your impressions of it.

another nice thing about a BB motor, is you can always just put on a different rear wheel...
I plan to lace up a couple of others to see which IGH gets me the best performance and durability.
perhaps a NuVinci, and almost certainly an Alfine 11... Which has two gears higher than their 8.

I was thinking the SRAM 9... But it, too, has almost universally bad reviews for durability...