Pros
no salary standards, so you can negotiate well during joining, especially if they are hiring for critical requirement. They will promise everything from green cards , career growth etc etc. all sorts of people will interview
Cons
I left a good job with TOP MNC because they promised to get the GC started immediately. I was hired for a project, in 5 months it came to an end , and suddenly i was asked to resign or go to India. When hired they said lot of projects across US , now i Know they have only 3or 4 projects , so very difficult to find other work I realized later that this was happening to even people who have worked for 8+ years, project ends, you go to India / take leave till next project. refuse to continue GC until next project. Nobody will talk to you except the HR person calling to find when you can resign. People who made all the promises will not even return your calls or emials. everybody disappears