I have Firestone Winterforce's on my car, and I have also had them on my Grand Marquis and Town Car. I had the rears studded on the Fords, but do not on my Eagle. As a winter tire, they are FANTASTIC. I have been completely impressed with them on every car....and I can really speak for them on the RWD Fords (because I always had two sets of tires for those cars). My Grand Marquis with no ABS or Traction Control kept up fine in Northern Michigan roads with my friend's Avalanche; I was never not able to keep up. On the Eagle they have been equally tremendous, and the tread design helps a lot with braking too. They are also VERY affordable in the world of snow tires
This brings me to the BUT......
Notice up top I wrote that it is a tremendous WINTER tire. They are awful on dry pavement. They are extremely soft, so they are miserable in normal temperatures, and they are extremely noisy. This is why your Blizzaks, Winter Sport 3D, etc command the premium the do is because they are NOT miserable to drive in all conditions. I would never put the Winterforce's on my Mercedes because I wouldn't want to see how they change the way that car drives on pavement that does not have snow. (That being said, I'd like to not have to put snows on my new Mercedes because, well, I have an Eagle
Hope this helps!!