For a game about trucking, surprisingly solid.
Even if the concept sounds dumb to you, Euro Truck Simulator 2 actually has a weird high-level production quality to it that many simulator games seem to just lack. All the features in Euro Truck Simulator 2 seem easy to find, and all are explained well enough so you know what you're doing. The game goes pretty deep on what you're able to do once you own your own truck, there is even character progression and skills. The world looks beautiful, and mini-scaled Europe is pretty dang fun to drive around in, especially since you can tune in to real radio stations from those areas and listen in.
Personally, I think Euro Truck Simulator 2 is worth a buy, it's a fun game that is a good example of what other simulators should be like. It's also great for playing causally as it's not a very intense game.