They probably aren't any better than what you currently have...if you make the switch, why not go to something like the Goodyear Marathons or the Maxxis? If you are going to buy tires anyhow, it won't cost you much more to go with those. You will hear both opinions in here, some will tell you Goodyear are great, others will tell you they aren't, but I think they are a better bet than the Freestars you are considering...and yes I know the ST tires all come out of China anyhow, but I have more faith in the Goodyear product coming out of there then the others.
2011 GMC Sierra 2500HD
2014 Rockwood 8289WS, Diamond Pkg.