I'd personally not race a half in preparation for a marathon. I don't have the experience as some others here in the marathon, but it's just personal preference.
Obviously a half will take lots out of you for several days no matter your fitness level. I feel if you train properly for the marathon you should have the confidence that you CAN complete the race on pace without the need for a very long “marathon race simulation.” So why not run a 10K and get the full effect of a race without messing up a week of training? Just my personal preference I guess. Maybe with a few more marathons under my belt I'd feel different.