I'm a tree farmer, so my experience isn't the same, but when I bought a rock picker, the salesmen were pretty aggressively pushing me in a different direction too. It's usually all about their commission. I don't blame them, it's their livelihood, but that means they weren't thinking about me and what I needed. I say stick with what you know. You already know what happens if a rock gets stuck. You know how to fix it. You already know how to deal with the nuances of that type of machinery. If steel on steel worked for you, then stick with that.