Back home now, adding a few points.
Nordic Cab seat turns into a flat bed for the kid. Useful as a changing "table", or for naps. Seat must be upright while towing, which leads to incredibly awkward looking sleeping positions, but our kid doesn't seem to mind, he snores away happily. Having two kids back there might actually help in that regard, as they can lean to each other. Good seat belts. We bought the optional suspension system, which makes the trailer marginally wider but supposedly adds comfort on rough surfaces. I feel that you can probably achieve pretty much the same result by simply lowering tyre pressure (at the cost of added rolling resistance though).
The standard foldable front wheel is small and flimsy, OK for hard, even surfaces but lousy in snow for example. The optional larger "jogging" wheel excels on uneven terrain, takes a bit of assembly, has to be removed for towing, makes for a
very long buggy and adds a locking handbrake. I believe considerable length is a common feature for all buggies equipped for jogging. Speaking of brakes, the standard version has none. The flimsy front wheel locks, but if the load is balanced in trailer even remotely correctly, the front wheel alone won't keep the buggy from moving. You're supposed to immobilize the buggy with a couple of straps you run through the rear wheels. I kid thee not. I consider this as the only glaring drawback of the otherwise impressive design.
We've towed our Cab maybe a couple of thousand of kms now. I've pulled it behind me on skis for about 70 kms. It's been used as a buggy, but to a lesser extent, normally inside shops we have first biked to. I have yet to tow it with bike in winter conditions (our kid was too small last winter), we'll see how that goes. I think the rear wheels are big enough for snow, but if it doesn't work out, I can always swap skis in place of wheels and pull it like a sled behing the bike.
--J
N.B. Nordic Cab can be equipped for skiing, but it is not a proper pulk substitute, if you're really into backcountry XC stuff. It will work OK on modern prepared ski tracks, with the wide skating lane in the middle. You will most likely block the skating lane, but it is doable. It will NOT work on traditional parallel ski track, or in off track deep snow. The skis are too wide apart. Get something like
Fjellpulken for those conditions.