My cousin has a Cottage XT, which is a big 1 man. I have fished in it with him for 8+ hours several times. We're both 6ft 200ish lbs. It's tight, 2 flashers, a buddy heater and limited gear, basically tackle.
Both my uncles have a Lodge XT. Fished all day a number of times with both. Plenty of room for a pair of buckets, 2 flashers, a buddy heater lots of gear for both. I have fished a handful of nights chasing crappies with 3 guys in the Lodge, it's do-able but minimizing gear for 3 adults is needed if you're going to go all day.
I would think the Lodge size or bigger will accomodate 1 adult and 2 kids no problem for many hours. Family of 4 (2 kids) or 3 guys with gear definately go with the Resort. I happen to like the bench seats too if thats worth anything.
As far as quality I don't think you can go wrong with Otter. Yeah they're on the heavier side but they're well made. One of my uncle's is on his 5th season and its held up very well, he tows it with an atv. My next shanty will be an Otter.