I've got two Bromptons, one 3 speed the other, until recently, a 5 speed. Both using Sturmey Archer hub gears. The 3 speed was wonderfully reliable, quick to change gears and felt efficient, while the 5 speed was always a bit more noisy, felt a bit draggy, took longer to change gear and used to jump gears, no matter how carefully I adjusted it. So I've recently had its hub replaced with another 3 speed and am very pleased with the results.
I've heard that the newer SA multi gear hubs are more reliable, but it is notable that Brompton are sticking with 3 speed hubs and using their cunning 2-speed deraileur to increase the ratios.
On the other hand, my wife has had a Dawes City Vision with a Nexus 7 hub which has been trouble free for 10 years; though I've heard mixed reports of them as well.