Its around a week with the Kwiggle, and every day since I got it I did a daily trip of 12-20 km, so by now I have experience with it and am quite used to it now.
Kwiggling is great! 
It is of paramount importance to experiment with the saddle positions, if it is not well-choosen, kwiggling can be very exhausting. Just two turns with the screw in or out make all the difference, and suddenly you drive with an average speed of 30 km/h and feel no tiredness at all, at least: less tiredness than on a normal bike. Correctly adjustign the saddle is absolutley important, and ignoring it, thinking such small changes cnanot make a difference is the biggest mistake you can make. Invest care and time on this one thing. It pays off tremendously.
Same is true for the height of the steering bar. It must match, and very well, then all will be good. If it is too high, it becomes exhausting again.
Driving is stable, I never, at no time, felt threatend or had a critical situation with falling backwards or forward when there was a hole in the ground or I had to brake. But you have to watch out, and anticipate the track surface and situations ahead. Carelessly dozing off and daydream while driving this, is no option here.
It feels a lot like jogging/running, as I said, or another comparison: riding a horse. Your bodyswing in the vertical is very similar.
I can unfold the bike in less than ten seconds now. Folding it takes me 20-25 seconds. Once the hands know by themselves where to grab and where to hold, its a thing of seconds.
If you are looking for a commuting solution, then look no further, this is probably the smallest and most comfortable solution you can currently find on the market. If you, like me, do not have the need for it, you may want it nevertheless, for me it is turning into a comfortable sports tool for low or moderate training intensity - after-training wellness already included, since you feel it while your ride, and do not need it afterwards anymore.
Very, very happy customer. I full-heartly recommend this.
They ship practically worldwide, but seem to have opened business in the US as well:
https://momentummag.com/the-kwiggle-...ng-to-america/
Do not worry for the shipping risk, the packing is very cleverly done, and good. I never would have had that idea by which they do it.
In Germany, and I assume elsewhere as well, they accept you to send the bike back if you do not like it after some days, since you cannot test it in a shop. They say they have a return rate of 3%, so of 100 customers, 97 seem to be happy with what they got.
The version with 3 gears, mudguards and lights, and a holder for bike panniers with certain connectors, costs around 1550 Euro. Considering the material and building quality and compared to other folding bikes, thats almost a steal. In Germany, delivery time is currently 3-6 weeks. A version with 6 gears is available, but its 2-3 cm thicker. An e-version is in development, but not fixed for a date due to the difficult economic circumstances.
Its a specialist and serves a niche, but in its niche it does what it does better than any other such bike, I dare say. Outstanding manufacturing and material quality, too. A reminder of that "German engineering" and "made in Germany" once had a meaning that was famous not for no reason. Well, the inventor is/was a machine building engineer.
I use average speeds of 25-30 km/h, and practically overtake all ordinary bicycle commuters. Acceleration phase is a bit longer and trickier than on a normal bike, but once you roll, things quickly turn into pure swing, and then you rush!
Not suitiable in the rough, for mountain biking, and such, You want plain and even track surfaces, the city and smooth road environment. Small stones and holes you find there, obstacles of 2-3cm in diameter, are no problem. Beyond that - be careful. Tyres are a limitaiton, they old out 100kg in total, of which 10kg are reserved for the bike. Driver and a small backpack/luggage must not exceed 90 kg. The frame itself would hold 250+ kg. The limit is set by the tyres, not the frame.
Super.
