CL pictures are all well and good but you cannot tell the mechnical condition from them. If you have an experience Brompton friend who can accompany you to check out the used bikes, I'd say go look at it. But, again, you're weighing $1000 for a new warrantied 3 speed compared to a used 6 speed. You don't want to have to put in hundreds to get it working properly. You might even consider paying a shop mechanic to go check it out if you decide you like it. Unless, of course, you can wrench on your own and you known the things to check. If it doesn't require much at all in repairs, remember it is probably pre 2017 and all the latest upgrades. Might not matter to you, and I don't think the newest stuff is on the B75 either. Worth a look.