I recently moved back from the valley and decided to stay and look for my next opportunity here, so I'll try to answer this based on my experience.
I'm not too sure what a "robust" community looks like, but there are some pretty solid people here and the tech/startup community is definitely growing rapidly.
Yes, the tech talks
in the valley are unbeatable, and I do miss having 10 different meetups to choose from whenever I have time. But there seems to be enough interesting things happening here to keep me busy anyways (and I heard from Kalv there are some pretty cool things in the pipeline for the ruby-112). And the good thing about being in a "small" community is that everyone knows everyone else, and people are generally more friendly/helpful.
As for jobs, I think there are plenty of opportunities here if you look in the right places and be proactive about reaching out to the right people/companies. I think I was being pretty selective in my search, but I still found a couple of startups working on some pretty cool stuff that I'm genuinely quite excited about. If you don't care much for startups there are also other "bigger", more established companies at different stages (from Mobify to Clio to Mozilla to Amazon).
Generally, I think good developers, especially good Ruby developers, are hard to find everywhere, and Vancouver is no exception.
[Tangent: I'm not sure how companies here would respond to non-traditional credentials like your program. There are a lot of these floating around these days, and their quality varies. You might have a bit of convincing to do, but once you landed yourself an interview you'll get the chance to prove yourself.]
There's no denying you'll have a lot more options in the Valley and pay are higher there. However, things, especially rent, are also more expensive down there, so the difference might not as big as it seems.
Hope it helps!