I bought from MM over CSI because they are closer to my location and tend to ship faster.
Yeah, I'm pretty close to STL- probably why MM shipped so fast for TBG
But then, I remember I didn't get Rebellion from them until well over a week after release.
I guess the best thing to consider is that Tabletop Release dates are fickle and unpredictable things. So is the post. Together, who knows what'll happen?