Anything made of steel will, at sometime, rust. Having said that, Rustoleum and some elbow grease (or an air sander if you have a compressor!) will hold rust at bay. None of the major brand of hitches will do a bad job, but some have features others don't, such as Wayne mentioned. We have a Reese Signature Series, now called the Elite Series, and it's selling point to me was two fold: everyone carries Reese Products so getting parts should they ever be needed won't be an issue, and it can literally be removed from the truck in less than a minute and leaves a nice clean bed with no rails to contend with. The most important factor when buying a hitch is to make sure it exceeds the weight of your trailer. That not only helps from a safety prospective, but later, should you upgrade trailers, you won't need another hitch.
BTW: welcome to the forum!!
