Unless you have ridden one, its of no use making a judgment call really. Taking it as luggage is a good thing, but not the only thing that's good about it. Its my daily ride now simply because it is fun to ride. After all, isn't that what riding a bike is all about. I don't use it for commuting on trains and buses as I don't have the need. Other than riding around our neighborhood, we like to take the bikes with us in the car to other areas. I hate the idea of hanging a bike on a rack mount on the car for a number of reasons, and one of the main reasons is theft. The Brompton folding bike I own can be neatly folded and placed in the trunk of a car. Out of site, out of mind. We did the bike rack and full size bike routine for many years, and we just got sick of it. Every time we made a stop either at a store or restaurant along the way, we had to worry about some scum bag ripping the bikes off the rack. The convenience of owning a folding bike is awesome. I can fold it up and carry it into any establishment wherever I go. I don't have to be bothered carrying around chains and pad locks and then coming outside from wherever I am visiting later wondering if the bike is still there. If I want to travel by airplane, for example, I can very easily. It folds small enough to fit the overhead luggage compartment without having to put it through on-board luggage and having to concern myself of it being damaged.

A lot of people have the misconception that a folding bike is for kids. That's the farthest thing from the truth. Yes, they ride a bit differently than a full size bike only because of the smaller wheels, but other than that the "fit to rider" is just like a full size bike. My wife and I found ourselves not riding our MBs anymore, so we ended up selling them. Try one out for yourself. You will be pleasantly surprised.

Cheers
Wayne