I'm car shopping now, too, although for an SUV or crossover (replacing an 8 year-old Chevy Tahoe with almost 120K miles on it). I buy pre-owned, so that does limit me to what's available. For what it might be worth, I can comment on how cars I've looked at appear to hold up.
I wanted to look at a Hyundai Santa Fe because they get positive reviews, have a long warranty, and we had a good experience with a Hyundai rental recently. What I did notice, however, is that the perceived "lower priced" pre-owned vehicles, e.g., Hyundai and Saturn, could not pass for new as some of the other vehicles could. And, they really weren't significantly less expensive than their similarly-equipped competitors. I don't know if this is a reflection on the vehicles, their previous owners, or how carefully the dealers prepped them for resale. I was much more impressed with the overall quality and condition of vehicles of similar age and mileage (I am looking for 2007s or 2008s) like the Honda CR-V, Volvo XC-90, Jeep Grand Cherokee and Volkswaon Tuarag (don't think I spelled that right). The Ford Edges and Escapes I've looked at seem to show the wear and tear a lot more as well.
I've never owned a Mazda, but friends have and they rave about them. I did stop at the Mazda dealer and ask about used CX-9s but there were none available. As to other sedans to consider, I am a big Honda Accord fan and my best friend's husband has a Toyota Camry that has over 250K miles on it and is still going strong.
One other comment I'll share (sorry this is so long) is that I've been surprised at how unresponsive car salesmen are, even in this climate where their sales are down and car companies are in trouble. I left a message at a dealership four days ago asking to see a vehicle advertised on their website and I haven't even gotten a return call. You'd think they'd be bending over backwards when they "get a live one."