I don't know anything about low-salary workers, but high-salary workers suffer from the H1-B system. At least half a dozen of my friends (from London) have been offered jobs (by Microsoft, Google, Six Apart and Qwest) in the US using the H1-B system, and let me tell you, it's a slow and painful process to put yourself through, especially considering that you're already uprooting your entire life. One friend was even considering moving to Central America and commuting for a few weeks at a time because the H1-Bs had run out for the year.