USE EXTREME CAUTION!
I can't say EmploymentCrossing is a "rip-off" but I can confirm its practices are highly suspect.
In one case, I spotted an ad for a position at a large, well-respected, national law firm. First, the position was supposedly located in its "Seattle office," which does not exist. Second, I could not locate the posting on the firm's web site. As a result, I e-mailed their HR director about my experience and suspicions, and she confirmed that the position was certainly not current, and may not have ever been legitimate.
In another case, EmploymentCrossing posted an ad for "Amazon.com, Inc." While that is the company's legal name, it's widely known simply as Amazon.com, so alarm bells started going off. Again, I was unable to find the position on Amazon's own web site.
Because the only way to apply seemed to be via EmploymentCrossing's web site, I started to upload my resume but it took WAAYYY too long for the simple text-only document to upload, so I closed my browser to break the connection, then ran a virus scan just to be sure. Nothing was detected, but it sure made me nervous.
The entire experience has ruined any credibility EmploymentCrossing may have had, and if I ever see another posting from them (usually on a blog aggregator like Beyond.Com, etc.), I'll check the company's web site and apply there if I find it. If not, I'll assume it's bogus.