I had mine sprayed in. I have had molded ones in the past but didn't like them. I found after time there memory would be lost and the fit would diminish. Maybe because of where I live(hot summers,cold winters)......I went with a diamond guard spray in liner,it's life time guaranteed and a wicked tough product. I'm sure there are lots of opinions on this subject. I hope you get lots of feed back to help you make a decision.
Lol, I thought I missed something by that response. Glad to know I didn't.
I would get a weatherguard. They are more expensive, but they are much sturdier and theft proof than cheaper companies. In my other truck, I just have a husky because its sole purpose is to prevent my straps from blowing all over the bed, I don't keep any expensive tools or anything in it. I don't even lock it. If I was carrying expensive things, I would have gone with a weatherguard. As to model, it depends on what style you want-- under rail, flush mount, high profile, as well as color.
I have a UWS black diamond plate cross bed tool box and really like it. Easy to access from either side of the truck and has plenty of room inside for storage. Found mine on craigslist for $100 and looks like new.