Is it easier to obtain work in US under F1 or TN visa?

I am a Graphic Designer interested in working in the U.S.
I have heard that it is a lot easier to obtain work in the US after you have attended a U.S school and have an F1 student visa.

Or is it sufficient just to look for jobs in my field there, and try to get a TN visa. Just wandering if I have a higher chance of getting something with US studies behind me. Please let me know what your experience has been, cos I would consider taking some more courses in my field, if it will be an in?

You can get optional practical training for a year after completing a full-time course of study under F-1, which can be extended for another 17 months if it's a science or math speciality.

Whether or not having a US degree helps with getting a job depends on the employer, it's impossible to say how much help it would be.