"Worth" is a market thing. Supply and demand. Usually you get what you pay for and I think it's true, when comparing the same brand and model of car, but many folk have have an aversion to big mileage cars so that adjusts demand down on them because of fear. Not sure of the reality, but the best statistical market evidence I can find is most extended service plans will not cover cars over 100,000 or 10 years. How up for taking a possible risk are you? Can you afford possible bigger service bills? You could have very few issues, but the older and the higher the mileage the more likely the bigger bills.... It not certain but more likely. You get what you pay for mostly, and many can't afford to take that risk or are risk averse (paying to avoid possible risks).
I bought a 35,000 FSH car last summer after looking for months (you need to see at least 3 to get perspective), but that's partly because I know I will put the miles on. Driven nearly 7,000 since Aug and loving it :)
If you plan to keep the car longer... say 5 years it's, less likely to be an issue. If you come to sell in 2 it will still be a average mileage vs high 100,000 mile plus car, the later will be harder to sell.
Personally if they are equal in condition I'd take the one with nearly half the mileage. But the car is for you, not me. Sounds like either would do.
Ask yourself...
Which car would make you happier? Maybe one has a feature you really want like leather?
As RedRobin says drive them both.... Your gut feeling will tell you something.
If that fails.... Ask yourself which one is the better colour, ie which one is the most
reflex silver? 
