I've read mixed views on the dual-shifter Brompton system, some people claim it becomes entirely automatic in use whilst others say there are both mechanical and utility issues. I've heard mention of the chain tensioner jamming up and not shifting cleanly.
For those who claim it becomes second-nature, is this always the case or are there moments when you end up making the wrong shift because somehow you thought you were in a different gear position? Do you have to consider the shift order or is it a case of flipping both shifters simultaneously? Or perhaps you have to shift up on the hub and take your pressure off the pedals, then shift down the sprocket whilst pedalling etc.? I can imagine that accounting for the shifting characteristics of hub gear and deraileur might be messy.