I just bought a 3 speed Brompton and tried commuting with it but for me, I have better bikes for commuting. I like larger wheel bikes. With the small wheeled bike I find myself spending too much time looking for potholes, cracks and being extra careful around street car tracks. With my larger bike and 32c tires, they just roll over most everything. The Brompton is twitchier while riding, which I am sure in time I would get use to but why? Again my other two bikes are better.

Folders can be advantageous to some but in my case it just isn't. I don't do multi-modal commutes and bike theft which is a concern, is well taken care of by my multi-lock secure bike compound at work. I don't need to bring my bike in to be safe.

Some posters have talked about efficiency of a folder, but it is not something I notice and even care that much about, as I am commuting not racing.

If my circumstances change maybe the Brompton will be the bike I take but until then my single speed Masi Speciale Commuter with FSA Metropolis bars is my bike of choice and my Masi with Ultegra 9 speed with Rivendell Albatross bars and porteur rack is my second.