I like the 2nd set much better; interesting backgrounds and better/cleaner lighting. But the "pose" is getting a little stale.
As much as I like cars, car photography typically bores me, so it really takes something new/unique/interesting for me to be wowed by it, as it's all the same really.
Now, the roasting marshmallows shot definitely falls into something new/unique/interesting, I just think it needs a little more help in post. It's hard to tell the car is in motion and there's a guy being dragged in the dirt. I'd try a tighter crop, bump the contrast, try to blur out the wheels a bit more, make the car actually look like it's going fast, and bring out the flame.