If you intend to be going for walks in the snow then for sure the roundabout is worth it.

Also realize that even if they are not all toddlers there may be days you want to just put them all in the stroller and go for a walk or need to go to library or playgroup or a park a distance away that involves being on a busy street and may like the added security of having the 2 year olds in the stroller too so spending the extra money and getting enough seating for all might be worth it. Also the resale value of the larger strollers is for sure there.

I have the foundations quad bought off a lady closing her daycare and while I like it the four seat issue has come up before as I only take kids till they start school so at any given time all 5 daycare kids could fit in it size and weight wise and yes some days would have been a lot easier just to load them all up and get to where we were going instead of taking too long to get there and back and wasting playtime at the park so to speak.