i would'nt rely too much on a web site for a company that charges to help with citizenship. while they may put basic eligibility information on their site it may not be totaly accurate (i'm retired from a u.s. government agency and encountered people who based their understanding of various program eligibility on fee and no fee websites, bsns., and 'lawyers' who either were grossly misleading or totaly unaware of actual/current program requirements).
also-if you're in a particular profession make sure and see what the particular u.s. state and town within that state you're interested in moving to requires. even government jobs that are identical state to state may have different qualifications within the same state (the job i worked in was identical whereever you did it-but in one town the offices required a college degree and in another a high school diploma-general contractors in my state can only do certain jobs up to a certain dollar amount-anything over that amount and they have to lic. and meet certain certifications-just across the border in the next state it's anything goes for general contractors).
o.k.-i understand the thing with weather i guess that would be appealing. but not knowing what public schools are like in canada, i'de have to wonder with the poor state of public schools across the u.s. if someone with kids would want to have to deal with the likelyhood that a high cost private school education is becoming the norm vs. the exception for more and more students here (no exageration-i know people in very moderate income jobs that rack up major debt so their kids can go-and it's not unusual for them to be paying out $1000 per child per month in tuition, fees, supplies...). and the parents that opt to send their kids to public can still end up paying an arm and a leg for childcare to cover the hours before/after school and all the time off for holidays and vacations. it seems that while wages would be appealing-the cost of living even in lower cost states housing wise might be a huge consideration.