Ive got one, had two at one point.
I dont use it as much now as I leave a rat bike at Paddington station for me 2×4 mile ride across town once a week this is beacause Id been lazy and locked a brompton to a sheffield and had it nicked from Strand. 🙁
I walk to the station at the other end as the very steep climb up the hill on the way home wasnt really doable on the brompton. So I walk it.
If you have the tyres pumped up very hard its a great bike to rag around on. Very stable and responsive. Very fast. But as soon as you let th epressures drop a bit it can be a drag.
You get the hang of folding/unfolding in less than 10 seconds.
I recommend the 2 speed for lightness, simplicity and short chain length.
s/h value is excellent as well as retailers are restricted on sale prices so no-one is letting them go less than RRP.