tbf, the gimmicky shifters have been 100% (over 18,000 miles) reliable and have stood up to some serious abuse from falls and bangs, both from the rider falling off and the bike falling over and quite a serious crash when my wife got the front wheel stuck in some tram lines. the bike is not marketed for hills but for commuters.
i do however detest the rear derailleur spring set up, it is very awkward to fit and gets clogged up in winter, rendering my 12 speed to 6 unequally mixed gears.
i hope the 8 speed is as reliable as you hope, but, on the brompton forum there have been issues with the hub, but this was when they first came out (might be sorted now).
if you couple that 8 speed with a md/sd/hss you'll have an amazing touring bike.