TN or OPT

I'm Canadian and went to university in the US. After graduating, I returned to Canada for 8 months and got a job offer (engineer) in the US. Before graduating university, I got an EAD card allowing me to work in the US through OPT. So before I enter the US, I want to figure out which one would I be more likely to get in with? . OPT or applying for a TN?

In the case of the TN, do I really have to convince them that I'm only staying for a year? Thanks!

Maximum of a year, you can stay for shorter periods. You can leave and re-enter and work using your current EAD provided your I-20 is still valid.

I'd stay on your OPT for the time being, especially considering your probably qualify to have it extended to 29 months from the original start date.

http://www.dhs.gov/xnews/releases/pr_1207334008610.shtm

thanks for the reply guys. I just found out that you can't be out of the US for more than 5 months in order for your F-1 to stay valid, thus the EAD is no longer valid. Looks like I'm going the TN route.