Actually they've renamed it the Ford Taurus, I don't know why they've had to rename it the Taurus again.
You have a great car, but 2 brake jobs in four years is a bit ridiculous. My 9-year-old Pontiac has had the front pads replaced (at 70,000 miles) but the rear are STILL original. My Dodge only had TWO brake jobs in 240,000 miles. You may have a problem with the discs or the pressure-relief valve in your calipers. Either that, or someone is telling you you need brakes when you DON'T (which happens an AWFUL LOT). As a mechanic I'm sold on Fords. One of ours made 325,000+ miles with less than $400 in total repairs.
As for the 500 being discontinued, the new Taurus is not only very similar in all dimensions and feel, but is also greatly improved. I'd recommend you try one out when your 500 is ready to be traded in another 300,000 miles.
They renamed it the Taurus because it wasn't selling well as the Five-Hundred, and the Taurus name was well established.
They did make some improvements on the vehicle though.
The issue with the rear brakes on this car was the material used in the pads. When they get wet, they swell, causing them to drag and wear out prematurely. Replacing them with OEM pads will only ensure having to replace them again not to far down the road. The only cure for this is after market pads.
I do agree that replacing brake pads twice in four years definitely indicates a major defect in some part of the brake system, or dishonesty on the part of the shop that told you you needed new pads.
At present my wife and I own a six year old Ford, a seven year old Ford, and a ten year old GM. None of them are remotely close to needing a brake job. The ten year old GM has over 110,000 miles on it, and still has well over 50 percent of the original pads left. I have very seldom ever had to replace brake pads on any car before 100,000 miles.