American Express Membership Rewards - SPG Business vs. Personal Card

I've been a big fan of the SPG card for a long time and recently added an SPG business card primarily for the signup bonus. When it comes time to pay the fees, I'm thinking of ditching the personal card and keeping the business card. It seems the business card does everything the personal card does plus gives discounts at Fedex, Hertz, etc. Am I missing something?

You are not missing anything. However, bear in mind that the Business card does not have all the consumer protections of a personal card. You can also convert your SPG personal card into an HHonors card with no annual fee.