For Provincial Nomination Program of Quebec, learning french is just a formality which you can do watching youtube videos and CDs and DVDs you get from Best Buy of Staples. One of my friends did the same thing some time back who says it worths buying those CDs and DVDs for beginners. He is doing better than what he was doing in US.

I have been to Canada couple of times, people seem contented with life and did not find anyone running for no reason as we do find in NY specially Jackson Heights Nepalese. Driving is not as fast as we do in US :). I am also on the verge of moving there permanently in a month or so.

Regarding coming to US, it is no big deal. You can do back and forth anytime but you need to have US visa until you become citizen. You can get citizenship in 3 years. Citizens can go to US, apply for job also without much hassles, no need to worry about H1b or other visa issues. If you lose your job, go back to Canada and again re-enter US start looking for job and continue, however you need to notify the Canadian Border Protection before starting the new job in US.

Payroll tax is pretty much similar to US taxation. Instead of sales tax, you will pay GST / HST which sometimes sucks. Electronics are little bit expensive than US. I-phone costs $60 per month (if you go with Virgin service), including unlimited incoming, unlimited outgoing within Canada, unlimited data and unlimited texting to USA.  Highways are similar. Vancouver is better than any best cities of US. New Cities like Calgary, Edmonton are way better than any cities in US in terms of public transportation. You will see trams, high end light rails. 

Digg into google if you want to know more cool things about Canada.