The Sturmey 8 is fine for small wheel applications, but the current version is very sensitive. My particular hub on my DT Mini is sensitive in gear 3.
Shifting is better than Sram 7 and almost as good as Nexus 8, but the shifter works in the opposite direction to Sram/Shimano, which makes it annoying if you hop between Sturmey and Shimano/Sram bikes. Also, the optical readout on the shifter is next-to-useless and the tactile feedback not as good as its competition. Efficiency in the lower gears blows the Nexus 8 out of the water and is comparable to the Sram 7. In the top gears, the efficiency is lower, but it doesn't matter too much as you're usually using them going downhill or with a tailwind.
According to the excellent guys at www.biketoolsetc.com
, they might have the new wide range Sturmey 8 by November/December, in both 28 hole freewheel, and 36 hole drum/freewheel/disc models. It looks like they are the best resource for Sturmey parts and will be carrying all internal parts for hub maintenance in the future.
It'll be interesting to try it out once it ships...