$300 annually isn't that bad compared to going to Jiffy Lube 4-5 times a year with an older car. Of course it's a lot more than if you do the same thing yourself, but eh.
They told me every 10k for the synthetic in my car, which is about ~10 months for me, and the 10k, 20k, and 30k scheduled maintenance visits are on the house, after which I'll probably trade in anyway.