I have been looking for job for almost one year in 2009. I got a contract job at beginning 2010. It's low paid, with little possibility of being permanent. Even more than that. The contract I got was an open contract, means it never ended. When they have job to do, they ask me to come. When they don't, they ask me to go home and wait for them to call me back. It looks like an on-call job. It was the area I am familiar with. I could not find other job at that time. So I accepted it. I worked so hard. I shared the same responsibility and stress with their employees. But the difference was, when project finished, they stayed, I have to go home to wait for new projects. But I accepted all of these. I worked hard. I don't care how much I was paid. I learn as much as I can. My only goal is to improve my skills as much as I can, in as shortest time as possible, so that I can find another job. Then after one year, I found a permanent full time job, my ideal job, doing totally different from this contract job. But the skills I learned in my contract job helped me get this new job. And because of my performance, my managers in the contract company provided me with very good references, so that I can get the new job.
My experience is:
1) You career development is more important than how much you get paid in a short period of time;
2) When you focus on how much you learned other than how much you are paid, your dedication will be paid, you'll finally find an ideal job you deserved;
3) You can quit an contract job at any time if you find a new job. They did not give you so much gerantee, so you don't need to be faithful to them like their employees. You managers of your contract job will provide you reference at any time. It's understandable to them.
In your case, I suggest you take the first offer to start working. Then wait and see if you can get the second offer. You can quit the first contract job even you have just started. If you cannot get the second offer, do the contract job and be as dedecated as you can, try to catch up in as shortest time as possible. Look for other job at the same time until you find your ideal job.
Good luck.