In regards to the 4BW, manual says change the oil when either the light comes on, 7500mi, or time-wise not more than a year.
My favorite thing to do is to head to Wal-Mart and get my favorite oil: Pennzoil Platinum which are one of the very few true synthetic oils made from natural gas, and depending on how good the factory oil filter is, I might get a high quality one from Mobil one while I'm at it.
GM says the break-in period is 1500 miles. I personally like to do the initial oil change around 500 miles on all my cars. Get rid of all those new engine wear particles, all the silicone and sealants involved in the assembly process(mixing itself into the oil), and then do oil changes religiously at 5k intervals, which should be very generous in my usage case and the high quality of the oil being used. Cheap insurance for ensuring engine longevity.
I use reviews of the dealership service department to find one with not only the best service possible, but the best service advisor and develop a relationship with them. They can make or break the experience when dealing with the ups and downs of owning a high performance car that will probably make unexpected service visits, especially on a 1st/2nd model year car. They can either be your advocate when dealing with the manufacturer on warranty issues, or they can just throw your ass to the wolves if you're an asshole.
So what's everyone's plan on maintaining these vehicles? Factory service and fluids, or DIY because you trust only yourself?