What an epic difference in the overall ride, especially if you live around many hills like me. I even find the mid and higher gears more pleasing. Everything makes more sense. The trade-off is that I couldn't use Brompton folding pedals, but I prefer MKS All Ways Easy Superior Pedals.
I got a 34T crankset from https://www.brommieplus.com — very professional and knowledgeable.
It was an easy swap. It was simply a matter of a slight adjustment to the derailer chain pusher and removing chain links.
I highly recommend considering doing it if you carry lots of stuff, tour, or face steep hills.
Brompton should consider offering smaller chainring options like 34T, but either way the customization is super simple.
by Total_Coffee358