From a bookkeeper's point of view using an EIN helps create a clear line between business and personal. You definitely want to pay yourself through your business. And one of the benefits of an LLC is the protection given to personal assests.
A few other positive things:
If you have a home office it creates authenticity with the IRS and can diminish potential push-back you could get by claiming the deduction.
Using an EIN helps prevent identity theft - stealing an EIN happens, but isn't as common.
It adds credibility to your business and I think that will help build trust with vendors.