Only have the gas stations in the US carry diesel for cars. Yes, that's still good odds, but it means if you are in an unfamiliar place, you may not be at a gas station that sells diesel. Plan ahead.
Diesel engines get much better gas mileage at highway speeds. They are very efficient. Not so around town. Do you do a lot of nonstop highway driving? Diesels make sense then.
The United States is a little different when it comes to the price at the pump for diesel. Other countries around the world, diesel is cheaper. But here in the US, it's more expensive. Supply and demand, as well as the kind of diesel we must sell.
Those two previous statements mean it's not exactly automatic to be cheaper driving by buying a diesel car.
Keep in mind that although it has improved, a diesel car still smells.
Toss in the fact that you pay more for a diesel car than regular gas.
So, a hybrid may be your best bet. Or not. Do the math.