I've been riding the K3+ here in Singapore for almost 3 months and have clocked easily 1000km so far, it is a very good urban commuting bike due to the small 16" 305 wheel and a good crankset size of 55T. I change it to 58T for easier longer distance cycling.
Here is a photo comparing it with a BrompNOT (It's a 3Sixty) : ibb.co/p05LL1r (Pls add "https ://" in front)
As you can see, K3+ is longer by the width from the handle grip on the right, so that's a 3" extra. K3+ is also wider due to the outwards folding of the handlebar. Overall it is not as compact as Brompton (or the replicas) but it is negligible. The weight of 9.x KG makes the ride very agile for crowded urban areas or around pedestrian walkways. When you cannot ride over, just pick it up and carry it.