^ Thanks for laying out the choices so clearly. 
I think the key here is that this student … doesn’t want to study Engineering but isn’t sure what they want - they listed Economics, Environmental science, and CS but don’t really know. So the Dartmouth or Columbia plan may not even matter. It sounds like it’s just a sort of escape hatch to placate others rather than a personal goal, something like " if after exploring my academic interests it turns out I AM interested in Engineering it’s not closed to me forever, even though right now it’s not something I want." (BTW the Dartmouth structure, with 1 year junior year when many others are abroad then graduation with one’s friends, is a great structural idea. )
In terms of selectivity (9%acceptance rate!), prestige, or academics, Colby is as strong as Waterloo. It’s a top NESCAC, something HS well wishers speaking about prestige likely don’t know. But ultimately OP will be the one who has to spend 5 years studying a subject they’re not interested in, not the friends or relatives pushing them to Waterloo.
(Even if friends&family in Canada haven’t heard of it, grad schools& employers have, and the alumni network is tight.)
For 30k a year (v.27k Waterloo) Colby is a really good deal, allows OP to figure out what they want, and is not a step down from Waterloo.
2 Likes