Which one is better; EB-2 PERM or NIW?

My company is willing to sponsor and bear the expenses to file my I-140 case. I was considering filing an EB-2 PERM, but some of my colleagues suggested me to file an EB-2 NIW instead. I am in a dilemma as to which one would be a better option. Can I ask for some professional advise on this, please?

to Ian:

The primary difference b/w an EB-2 PERM and EB-2 NIW is that PERM is employer sponsored, whereas NIW is self sponsored. Since NIW is not tied to your employer, you will have more freedom in changing jobs. For EB-2 PERM, if you change jobs, your sponsoring employer has the right to withdraw the I-140 petition.

Also, NIW is faster than PERM. Mine was approved a lot faster than my friend's PERM.