I'm a bit exasperated with my Sturmey Archer 5 speeds and am curious about the two versions of the SRAM hub that seem to garner almost no attention whatsoever, the 'Cargo' and wider-range version.

The Sturmey hubs have changed over the years so I don't know to which model the efficiency chart I saw pertained which listed gears 1 and 5 as being in the 80s. I have several instances of the ball-locking type and they have irregular efficiency issues in the middle gears too.

I think I've read that the SRAM 5 speeds are popular in parts of Europe, and that the mechanism is very different from the SA hubs, presumably resulting in greater efficiency. The downside is that they're heavier.

Any advocates of the P5 here?