Sorry, signed up to chip in, because I have had a Mezzo D9 (2008 model) for over two years and use it nearly every day. So I have a fairly good experience with it.
Basically, it is a good bike with some pretty serious design flaws...it rides very well, apart from an annoying vibration in the stem. It is pretty fast and nippy and easy to control (once you get used to it). It is ever so slightly undergeared - the lowest gears are too low to be useful, unless you are completely out of shape and the highest gear could be higher for going down hill quickly. Having said that, for urban riding in London I hardly ever use anything other than the top three gears, spending most of my time in the top gear as I got fitter and more used to cycling. So much so that I even considered turn it into a single-speed folder.
So what is the problem with it?. Well, it's just got all sorts of bits and pieces that need to be just right - otherwise things go wrong. It is certainly not a low maintenance bike! The gearing system is very sensitive to weather and the folding mechanism interferes with it. I have had so many really weird problems with it - including the chain wrapping around the cage plate and the pulley and twisting the whole mech out of shape. I've also had twigs getting stuck in it, and on one occasion had it just inexplicably get stuck and the chain snap while I was cycling quickly. Some of these problems may be due to my utter incompetence at bike maintenance, but the whole gearing system seems very sensitive and easy to mess up.
Also, the seat post clamp should be considered a perishable component, like break pads - I am on my 4th! the problem is that Mezzo does not provide replacement seat posts! Luckily the guys at
Evans in Chalk Farm are really into bikes and like a challenge, and they always manage to re-purpose some old Dahon seatpost clamp and use that to fix it.
So would I buy the Mezzo again? I don't know really, I wish they had a version with 3spd internal hub gear (which I think would many of the problems) - I know they had the I-4, but not sure that is being made any more.
Also, when I bought mine, wiggle had it on a clearance price which was about £600 - the full price has already gone up a lot now, and I am not sure I would want to pay £800 for it. If I still had space restrictions, It would still be top of my list, but perhaps an up-market dahon model would be a better bet if I wanted something maintenance free. We have moved house, so storage is less of an issue, so I reckon my next bike would be a full sized bike rather than I folder, but I won't be looking for a bike yet as my Mezzo still does the job.