Had a 15'4" Highsider that I just sold. I took that thing everywhere, but wouldn't recommend it with kids. It was much more stable than a canoe but still tippy. Also have to be extra careful on the tailwaters due to the fiberglass.
There is quite a bit of variance between Gheenoe models. If you're considering having kids along, I wouldn't go with anything smaller than the Classic. The Low Tide 25 would be best, but it's a bit pricey. The build quality is excellent.