Hi,
I thought it may be beneficial to share my experience of the 457 visa, which is a very positive one. I fully appreciate that everyone has an individual experience and while it may not work out for some people, it is very successful for others. I would also like to point out that the 457 is up to 4 years and the employer does not have to offer the full 4 years.
My husband and I moved to Australia in November 2012 and our first 457 visa was for 12 months. We took the risk and when I wanted to change employers I emailed some employers asking if they offered sponsorship and no one was negative. In fact, I changed employers and they have sponsored me for 4 years on a 457 visa. For some people they don't want PR and they are happy to be on a 457 visa. We have had a great experience in Australia and may go for PR in the future but for the time being we are happy on the 457.
With regards to a dependent finding employment my husband had no trouble at all. The only difference is that he cannot be offered a permanent contract due to the visa, however he has a contract for the duration of the visa and when the visa was extended he just provided a copy of the new visa to his employer.
In addition, we have had no problems obtaining credit cards and car finance. My husband required an operation and this was all covered on medicare. I can honestly say that the 457 visa has not felt like a barrier at all and we feel very privileged to have been given the opportunity to live and work in Australia for as long as we have. If we want PR then I think Australia and its employers have the right to be picky - the 457 is very clear in the guidelines that it is a temporary visa.
I am sorry that you have not had a great experience and I wish you luck in the future.