Most of my travels end in destinations served by smaller aircrafts, so I always check my bigger piece. I don't want to be encumbered with it in airports waiting for customs etc, especially when I have connecting flights. I consider that part of the price of my ticket is for NW to handle my bags.

NW has never lost/misplaced an item. The only minor problem I ever got was three weeks ago. The MSP-AMS flight was delayed by 4 hours, and I missed my AMS-MAD connection. I was promptly rerouted via CDG, could not find my bag on arrival in MAD but was immediately told that my bag had not travel with me and would arrive on a KL flight within the next 30 minutes. This is the longest I have ever waited.

I would probably have a different tactic if my endpoints were served by widebodies.