I've done a ton of research on the Vancouver area even though I was most interested in relocating to Victoria on Vancouver Island.
Here are the downsides -
You can't rough ridin' get in. It no longer matters if you have tons of dough, or if you have a successful business you could relocate there. Unless you get a workers visa for a job that's in serious demand, or get an investment from a Canadian investment firm, it isn't going to happen right now.
Eventually there will be a huge megathrust earthquake in the Cascadia subduction zone near Vancouver Island. There's only a 10-14% chance of a 9+ earthquake happening there in the next 50 years, but that's still a high risk when you consider how bad it would be since they aren't all that well prepared. The odds and severity will keep increasing as time goes by.
I've spent the last few years researching the US and Canada for relocation options. I can work from anywhere and I'd like my kids to have the best education I can afford. Manhattan is overpriced for what it provides young families, but to be honest I've been kind of amazed at how well it stacks up against other places. We're still traveling around to prospective spots so we can make a final decision in the next few years.