I have Sturmey-Archer hubs on my Brompton bikes. One issue with the hub is the complexity of self-maintenance. While the S-A is relatively simple for a hab and there is a lot of documentation on the web, others may be more complex. I really like to ability to be able to maintain my bikes myself. Yes, the hubs are more expensive, but I personally don't care too much for that argument (since it's already a pretty expensive bike anyway). But they are very reliable, this I care about.