I bought one of the 700s with the heavy barrel in .300 Winchester Magnum and a 700 Mil-Spec .308, also with heavy barrel. Both were bought new and are 5R guns. Still working with various loads, but each rifle shoots very well. I also have a 700 VS in .308 that I bought new at least twenty-five years ago. Of course, it has whatever conventional rifling Remington was using at that time; always been very accurate. I haven't done a formal side-by-side comparison, but I'm pretty sure the 5R .308 is no more accurate than the 700 VS.
Regardless, a comparison of only two rifles wouldn't mean much. Whether a good 5R barrel offers any advantage (other than from a marketing perspective) over a good conventionally rifled bore probably remains to be seen.
