The Duratec really was a triumph in engineering over the Vulcan. If memory serves, the Duratec comes with 200 hp, and it seems the Vulcan was in the neighborhood of 160. I live in Jacksonville Florida, which is very flat. I have mixed driving, city and highway. Without AC, I get 26 mpg, with AC I get 22.
I am a little bit of a gearhead, I like to tinker. After I sold my Vette, I turned my attention to the Duratec (BTW, my car is a 2001 Mercury Sable LS Premium). Try to find heads for these cars, or performance parts for them. You can't. The reason is they are durable. And Ford did a nice job getting a lot out of the engine. Despite being one of the best selling cars in America, you can not even find a Cold Air Intake that is made specifically for any Duratec engine. My point here is to let you know that any one of these cars with the Duratec engine, that has received a reasonable level of care, will provide you with excellent transportation.
Regarding maintenance, there is almost nothing outside of oil changes that is required. Transmission fluid should be changed out at 60k, plugs and wires at 100k, transmission fluid and filter at 120k. I have 93k on my car and just could not be happier. It looks good, rides well, and fires every time I touch the key. And since there were so many made, prices are reasonable and selection is great. Just ensure you get one with the 24 valve Duratec engine and everything else will take care of itself.