Full-Time Consulting vs % basis at Client Site

[navigatingUS]

First post on the site!

I'm on F-1 OPT (with a B.S. degree) working as a consultant in US. at a client location through a vendor and further through an employer. I have quit the current employer who dint hold up his promise of filing my H1. My dilemma is that I have two offers from two consulting firms- one (company A) requires me to work full-time through them at client sites. They say they don't need a client letter because they have their own products/ services. The other (company B) will be on a decent percentage basis, but they have to find me a new project that can give a client letter and file a H1 with it. Company A's pay is really really terrible which is a big turn off point.

My question is- considering rejection rates after travel to India, and approvals of H1 in general, is it safe® to go with the full-time consulting company or the % basis company? Since the H1 quota is already open for 2013, do I have time to actively market myself, get an offer, gain a client letter and file the H1 within the month or should I jump on the extremely low-paying full-time who don't need me to immediately find a new project?

Thank you for your help.