Different Folders have different uses.
Which one is best depends entirely on why you want your bike to fold.
1) To store it in your Flat for security? Then a "full size" folder may be best. Dahon do several MTB-style folders
2) To take on Public transport? Hard to think past a Brompton.
3) To carry in your car for rides down a tow-path? Dahon make several 20" wheel bikes that would suit.
I've owned a Dahon DH7 (hub gear) and I now own a Brompton M3.
I want a bike I can quickly fold and take into a Cafe after exploring a town or city. For me nothing comes close to a Brompton.
They ride very well, much better than people who never rode one will say. The Dahon was marginally better I'd say.
The Dahon was more of a faff to fold and the final, folded, package was slightly too big to be slot under a cafe table.
The Brompton fold encloses the chain. That's a HUGE positive if you plan to be carrying the bike and lifting it into cars/trains/buses.
The Dahon left the chain and drivetrain exposed totally. You need to remember to avoid getting oil on your car carpet or anyone stood on the other side of the bike.
You won't lose any money if you buy a used Brompton. Pay £600, try it for a few months and sell it for £600 if you don't get on with it. They really don't depreciate much lower than £600.
Oh.. the luggage options, that utilise the Brompton front mounting block, are superb. Unclipping your bag and folding the Brommie is a genuine 15 second job.
This is me doing a fairly average fold/unfold. >>>
CLICKY <<<