I use an S-RF5 with my Brompton and have had 3 different bikes with instances of the hub. I've swapped internals around between them & tweaked the hub by converting it to oil lubrication so I've gotten to know it well. Despite that, for some reason on one bike I couldn't get rid of a notchy feeling in the drivetrain and I couldn't see any reason for it besides the hub... but after switching internals out the rough feeling was still there. The hub which is installed on the Brompton has functioned nearly flawlessly since I switched the 13t sprocket out for a 14t. A 13t sprocket is small enough that the chain engages/disengages with it poorly and the drivetrain feels rough. A 14t is just large enough that after wearing the chain in very slightly it runs smoothly. I'm happy to use a larger chainring for the improvement of the larger sprocket.
You have to be careful in getting the axle width and OLD spacing right. I used a 175mm axle and it needed shortening slightly.. which is something to undertake cautiously as part of the axle is hollow.
For me the wide range (more recent) version of the hub is too wide in its gear spacing so if I were to use that I'd want to incorporate the 2 speed shifting system for a 10 speed set up.