I've built up bikes for my friend's shop with SA IGHs and was totally unimpressed. They worked poorly and were hard to setup. These were 3 and 5 speed IGHs.

By comparison Shimano IGH bikes were easy to setup and worked well.

I'm running 1 Alfine and 2 Nexus 8 IGH on my personal bikes and like them quite a lot.

To be clear my entire SA experience has been 6 bikes so I'm just passing on my data points.

I've got a Shimano dnyohub on one bike and like it a lot. I have never used a SA dynohub.