The Mezzo has a slightly smaller fold than a Birdy, is as well put together and shares the massive advantage of a lack of central hinge. All it lacks is suspension. But then again, one of my friends with a Birdy rather envies my Mezzo because he prefers a non-suspended ride. Retail price is around £550-£600, widely available from Evans and Cycle Surgery, etc and very good value. Been thrashing my Mezzo d9 for a full year on a daily multi-modal commute and no problems at all. Give one a test ride.
He has a limited budget for good reason, as much as he would like the Birdy. He borrowed one yesterday and told me later that he thought the ride was superb (smooth, enjoyable and fast enough), the weight ideal, the build quality what one would expect from something bearing a German marque and the design very eye catching.
What he did not like the folding method because he felt that on a wet day, the method would involve holding a wet and possibly dirty bike by the wheel(s). Looking at both the pictures of the folding method as well as a video and it does appear that one might get dirty hands with each fold.
There is a lot in what jnb-rare says, if you have set your heart on something and are then forced into a compromise, usually for financial reasons, the compromise never satisfies, it hasn't got a chance, because your always thinking about what might have been. Over a period of time differences in cost price errode and you are for ever kicking yourself. When I was younger I once bought an Alfasud, when what I really wanted was a GTV, good as the sud was, it was never going to be the full deal. If your friend really wants a Birdy tell him to save up (and maybe allow some extra for a pair of gloves), or else give a full suspension Downtube a try.
I read that there is some criticism of the gearing?
Its maybe a bit under-geared - it would be good if they'd built the rear wheel around a Capreo hub, enabling it to take the Capreo cassette, which goes down to 9 teeth at lowest gear (search the forum for more of my rambling on it, and some proper gear ratio comparisons). But to be honest, the gearing is pretty decent for urban commuting, even if I don't tend to use a couple of the lowest gears. I certainly don't feel that constrained by lack of an extra high gear (even if occasionally it would be nice, its not vital). And most importantly, it feels pretty fast and its fun to ride. Certainly worth a test ride if you want a compact, quality folder, don't want to be another Brompton-clone and can't afford a Birdy.
Matt52, thank you for your answer. In fact I took one out at lunchtime and I agree with all that you say, except that I did miss an extra gear or two. Otherwise a lovely bike; would it take Big Apples?
Can see why you might want to try Big Apples - I guess a _bit_ of suspension might occasionally be quite nice. But I'd be a bit worried re the built in mudguards and the caliper brakes, both of which might be a bit of a tight fit for Big Apples (not that I've tried). But as the bike is stiff and strong as anything, its no real big deal to take bumps by standing on the pedals.
On gears, I think it _might_ be worth sometime getting the rear wheel rebuilt to take a capreo cassette. But until I run out of better things to spend £150 on (new hub, new cassette, wheel build), I probably won't bother. And its not as if the bike is going to be taken to the races, most of the time I'm in middle-ish gears between lights, and if I really want to put some extra speed on, I just have to pedal a bit faster....
I took a Jetstream P8 out for a quick test and was impressed with the ride. However, there are no Birdy's around for me to try (not until next spring, says the one LBS that sometimes carries them), so I can't comment on a comparison. You can compare "the specs" for current and older Dahons right on their site.