I don't have much experience changing oil/filters, but the worst so far is on the Sentra QG18DE. It's located on the back side of the engine towards the firewall, one must wrap their arm up and around, you don't have much space to fit a filter wrench on it, and not much space to rotate the wrench once it's on. Also have to ensure that the exhaust is wrapped with something as there is a flex pipe that is located all-to-easily to spill oil onto.
sambojoho said : "I always check for ease of service now before I buy a car." I am definitely doing that for the next car, so far the Corolla, the Yaris, and the Fit are my choices...