Somewhere in some city there is always a shortage of a any job. They can bring in foreigners if they can't find qualified people in the local area, there might be a million IT tech jobs in silicone valley, but try to get someone in the middle of Texas and there could be a shortage.
THe person who said ARizona was completely different to elsewhere because the people were friendly, relaxed and non agressive. thats weird because having been to california(basically most of it, a traveling trip where we did a huge circle around the state), ohio, colarado, arizona(briefly), new york state well, not anywhere did i find hostile or rude people. In fact new york was full of incredibly nice and helpful people, no one was hostile it was a great place. even late night/early morning when in london you'd be worried about gangs and big groups of people walking around less well lit less busy area's was completely fine, relaxed and bumped into a couple people who asked if we were lost and were helpful.
As for moving there, its a pain, as are most places. Aussie is AFAIK incredibly difficult to move there. A friend of the family, older semi retired couple got permission moved over there, bought a house, spent a couple of years there and despite bringing money through their pension and buying goods and spending money there they were denied permission to stay and unceremonially told to **** off home. We don't think its when my friend/their son went to visit and at immigration they asked if he had a criminal record. he replied "is that a prerequisite here then?"
First thing to do is read up on the immigration site in the states, then some advice sites, see what jobs that your qualifications could get you might be a good way to get you in there. You might want to work a job you can get, but don't really want for a few years to get ya green card, then move to a job without shortages but you really want. There should and could be ways to move there, often its not easy or quick but definately possible. It could depend on what degree you have, i mean a lawyer might have a really small chance. as well, they are everywhere , where as like i said tech guys are often in certain area's so other area's can have shortages. But if you are "that" damn good or have a great degree, masters/phd and you can do a job better than anyone else that can also make a difference.
As for days off and work ethic, yes to a degree americans do work very hard, but except for your average 9-5 tech support or working in a shop job most 9-5 jobs here end up being jobs you take home, work late and do lots of unpaid overtime anyway.
You can certainly get overtime over there, in almost any job you do get more time off the longer you stay. AFAIK an average idea there is 10 days start, 3-5 years in you get 15-20 days, and 10 years often gets you a month off. you can also negotiate for more time off in lew of a pay bump one year get a day or two extra. but remember that 10 days is ontop of LOTS of extra days off you get there already. once you get far along in your career you often get a lot more days off there than anywhere else, after 10-15 years plus some great negotiation you can end up with 1-1.5months off a year on top of 4th july and all the other normal holidays. Not really sure how common it is to take sick day pay in the UK, i've never taken any, but its fairly normal to take spare sick days as holiday over there, every year or two when your sick days have added up and you they won't count for much longer use them up as holiday is a fairly widely done and accepted thing.