Whereas I first fancied an electrified foldable long-tail cargo bike Haul-a-Day by Bike Friday (USA), but the final price of over 5.400 € (including import tax to Europe) was a bit discouraging. Meanwhile, Bike Friday came out with their very similar Ever-E-Day Family.
For economic reasons, I thus fancied for an electrified and foldable Tern Cargo Node (3.200€) over the non-foldable Yuba (also USA) Mundo (3.900 - 4.400€) or Curry (4.250€), in the back of which you can place two child seats. However my wife preferred to have the kids in her field of vision, so I came back to the e-Muli by Muli Cycles (Germany). We had encountered this bike at the first cargo bike ferry a few years earlier and tested its possibility to be taken onto the Berlin metro, due to the foldable pannier which I've otherwise only seen on the Gazelle Cabby (which is 2.55m long).
The (e-)Muli is only 1.95 m long, so it fits into most elevators, on bike carriers and into large cars. The first e-muli comes with a Pendix engine made in Germany. Unfortunately, the small frame (which fits small as well as people as tall as me at 1.87m) only fits a 300 Wh battery, but Muli therefore offers a second battery with another 300 Wh. Having two batteries is convenient because one is normally always charged. The engine assists with up to 50 Nm, which means you may have to push the bike when it gets seriously steep and in this case you might miss a pushing aid. Instead of a display, you get an app which originally included navigation (which was dropped at some point) and indicates the battery status in percent, the current speed as well as remaining range and pedalling frequency.
In terms of equipment, I chose a nice color, the second battery and the luggage rack, which resulted in a price of 4.800€. I upgraded the bike with an AXA Solid Plus frame lock with a cable, a bottle holder on the stem, a decent battery light, an eZhitch coupling for our Thule carrier, nice handles, my old motorbike parking cover, a Bluetooth speaker attached with an old rubber chamber and in the winter we use a bean bag with lamb fur coating. The rain cover may be neat if you don't have a garage and you don't feel like covering your bike whenever rain seems probable. And soon I'll opt for reinforced Schwalbe Big Ben Plus tires, because glass quickly gets through the Big Apple balloon tires and their profile is not suitable for slippery terrain.
So after a year, what was my experience? My wife took a few days to dare to ride the bike, but now uses it more or less on an every day basis. She once fell when she turned into a gravelled parking lot, but the bar steering the front wheel is constructed so as to fold up in this case and took to damage whatsoever. Especially when she was very pregnant again, the electric assist helped her stay mobile. Getting out of our block is easy because the bike has a very short radius, and for every day use, the 50 Nm are largely sufficient of an acceleration, even with two kids and another one in the trailer. For shopping, the rack or a trailer are good to have, because besides two children the transport box won't fit a lot more stuff. I had one flat tire in the year of cycling something like 5 km per day, and the issue was settled with basic tools and a 17 cm key for the trailer adapter. The only other technical issue was rain getting into the battery holder, which unfortunately didn't come with the available neoprene cover. Other potential issues are the plastic cover of the stand which suffers if one is not strong enough to lift the (loaded) bike to park it on the stand. And people with weak hands may have trouble opening the seat post clamp, which is why I considered getting an adjustable and spring-loaded seat post, which is bloody expensive though. Therefore, my wife often rides around with the seat post loosened, which will at some point kill the seat post I suppose. This problem obviously only occurs if two riders of different size use the bike and one of them is not capable of handling a seat post clamp and it is not due to the bike itself but to this constellation of riders using one and the same bike. Update: applying grease every two months solves this issue.
On the weekends, we cycle out into the surrounding hills, where the range drops according to the load and physical capacity of the rider, and the second battery often becomes necessary. Roughly, me as a former bicycle messenger with our three year-old, water and basic tools and 20km with 400m of altitude difference and the first battery is dead. Without real altitude, I managed to cover almost 70km with one battery, only using it for slopes. Compared to a Bosch drive, the charger's you might find along the way will probably not work for a recharge, but usually the two batteries were enough for a day of cycling something like 60 km including 1000 m of altitude, with two large backs packed with basic travelling gear (no camping gear). Even if you think of some more serious long-distance cycling, charging up the empty battery during a two hours break should allow to cover over 80 flat km per day with heavy equipment.
Compared to my friend's Spicy Curry (Yuba), the hub gear turned out to be less sensitive to use, but then they often carry an 8 year-old, a 5 year-old and a baby plus shopping, all without a trailer. Considering this, the chain gear might actually be a better option because you can choose for a gear rim allowing to climb serious slopes. They are however very happy with their equipment, too. Service seems to be a different issue: I've only needed assistance when rain got into the battery holder (soaking out the water with a paper towel solved the problem, a vacuum cleaner would probably have done the same job).
Update: after about 18 months, the kick stand (Ursus Jumbo) was dead. Muli cycles sent me a new one for free after about two weeks.