It depends what you want to use it for. Longbikes are great for wee passengers as they tuck in behind the rider. I carried two young children on our Kona Ute for years and still lug the 9 year old about (she can’t ride) when at Center Parcs or riding on Sustrans paths. It’s easy to fit a stoker bar to the seatpost and bolt on a child seat and bmx footpegs. It’s long enough to carry two kids and panniers. You do need to be careful when loading and moving off, it is quite high and unstable until moving. Riding position is just like an mtb, I did Pedal for Scotland on mine, it was perfectly comfortable. Surly BD and Yuba Mundo seem heavier, lower and sturdier than the Ute.
If carrying serious loads, a lower platform would be more stable. A trailer will be the cheapest and most flexible (sorry) option as you probably already own a bike. Plus the load platform is very low. Dutch cargo bikes with huge boxy load areas may be perfect for the job but they’re very expensive and less easy to store or transport. Conversely, a longbike fits on an Avenir Tandem Carrier.
Think about what you want to use it for and decide from there.