In reply to ByEek:
Firstly, I'll fess up that I have a Brompton for commuting. Its 16 inch wheels and very compact fold are just what I need, since I have to get it in the boot of a citroen C1 for the first part of my journey. It was also fortunate that it was the only folder available through my CTW scheme.
However, consider the following points before choosing a folding bike:
Does it need to fold up really small?
Where do you intend using it - is it hilly, exposed to wind? My route is both, and I'm glad some days that I have 6 gears.
What are the road surfaces like? 16" wheels don't roll like 700c, steering is 'twitchy'. If surfaces are bad, bigger wheels may be better.
Do you need mudguards, racks etc? I go 7km each way and use a rucksack, so its mudguards only for me.
Lastly - ride position - try before you buy. Some folders are plain weird! The Brompton is OK, but very 'sit up and beg' AND the whole bike flexes a lot due to the extended tubing (steerer, seatpost, frame). Don't get me wrong, its a great tool for commuting, but I wouldn't choose one over a conventional bike, were it not for the need of compactness.
N