Yes, I think it makes sense to have gotten a non-separable Moulton with that complicated frame.
The Brompton isn't so much of a performance folder, like Bike Friday or even some of the better Dahons that are coming out now, but it really folds better than anything else, which makes it ideal for city riding. There are a few custom options for upgrading the gearing out there. Some people have set up derailleur systems on them, and there's the Rohloff 14-speed hub gear (the downside is the weight), and the Swiss Mountain Drive, which is like a front hub gear that fits in the bottom bracket. If we moved to a place that had hills, I'd probably spring for the Mountain Drive.