I was wondering about changing ours, as most of our firm's travel is on BA, but then there lots of other stuff goes on the cards too. And I wasn't sure it was worth the hassle to change over.

As you say, our normal Corporate AMEX cards top up the MR Point nicely, as you know:

Spend Company Money = MR points = HHonors Points = free stays at Hilton&Conrads ^ ^