With regard to wheel size, the Helix has 24" wheels, which I'm hoping is going to offer a ride that compares reasonably well with full-sized 26" wheels. I remember testing out a Brompton when I was first looking into getting a folder, and despite the Brompton really living up to the ideals of being a bike that folds small enough to put in a suitcase and travel with, with its 16" wheels it was far too twitchy and not that much fun to ride. Bromptons are also quite expensive and there are lots of custom parts. In the end I got a Tern Verge x10, which has its own set of problems (the folded bike is awkward as hell to carry, and there were some recalls, due to folding joint welds welds failing which could have led to serious injuries or deaths), but is so much better to ride. The reason I got into Helix is because I want a folding bike that is actually compact, light and easier to carry folded than unfolded, but rides more like a regular bike.