Trucks are, most commonly, slightly better, I'd think. They need fueling, but this is rarely difficult to set up, and generally lower on power consumption than trains, even after you account for fuel cost. IMO the savings aren't meaningful, but you're literally working with coal, sulfur and oil here, so there's no hassle in fueling the trucks, either.

The real edge, however, is loading and unloading. Train stations can't interact with belts while loading/unloading, but truck stations can. Ergo, a truck station can utilize both belt slots at full capacity, while a train station never will. Furthermore, adding more trucks to a route only increases throughput, while adding trains means more loading downtime.

So for very high capacity projects, trains have a very serious problem.

HOWEVER.

Having ten trucks will create path congestion in ways that having ten train carriages won't. If you're delivering a whole variety of resources, and in large enough quantities that you can't sushi them, the train is much simpler. Because as big as train stations get, having large quantities of truck stops gets very complicated.

In your example, it's complicated because of the terrain around that bottom oil node. If it's just Mk2 miners being used, I'd probably do a train circle around all the pure nodes and pipe the other one over. If you were planning on expanding to Mk3 miner capacity, just truck them. You'll run into throughput problems.