in our migration, we used FedEx rather than using in-house shipping.
We had some problems. We would write on the box, "Do Not Stack"...and they'd always come in stacked three high. We were also trying to re-use Dell boxes for our mostly Dell servers. Worked great, but Dell did not intend these boxes to make more than one trip...we got maybe 3 trips out of them.
Another thing to consider is the speed of shipping. We used overnight shipping...which cost a lot, but we only had 24hrs of down time at most. It also beat up the boxes a bit more.