Why if one's starting point in the question is Brompton, would the next two be Dahon\Tern?
If one's primary and secondary bike needs don't demand smaller folds, 351 16 inchers, then there becomes fewer reasons to stick with a Brompton's limitations. Made in UK, hand built, lower depreciation, all great reasons to still pick it, but more along the lines of luxury niceties.
Even if one is sticking to smaller wheels\folds, shouldn't it be the Brompton \ Bike Friday \ Frog \ Mezzo or Ori \ Dahon \ strida \ Downtube Mini \ Citizen Tokyo\ etc. question?

I think giving where I live in the world, if I didn't have to worry about money and thieves, I'd go Bike Friday, over Brompton. Although that tikit would be rocking a Brommie front bag, lol. If I didn't have to worry about multi-modal commuting; it'd be a pocket llama.
Can't get a Ori\Mezzo, nor Frog CA stateside.
Brompton's just aren't packing 8/11 and same maybe even worse $/thieves. I really like the raw laquer look, though.
Used Brommies can hit Curl overlap.
I guess Dahon Curl is still a $/thief issue, but benefit for gearing, less proprietary and a year of LBS support?
I guess this leaves me languishing in Downtube mini territory, which won't handle grocery trips and eyeing 25 lbs or lighter 20" if they're below Curl\used Brommie prices and wondering how much I'll regret it or not on the flights of stairs, train\bus.