Re: 6,5x55 dies
Forster and Redding both make excellant seater dies. If they're "worth it" or not depends on the potential accuracy of the rig, the shooter, the skill/knowledge of the loader and how well he can develop a good shooting load. What I mean without a lot of case work is there's no significant accuracy benefit over common dies which are, after all, quite good. There's a LOT more to a good seater die than a simple micrometer depth adjustment screw top. Actually they are mildly helpful during initial set-up but I really don't much care if my own good seaters have mic tops or not.
I wouldn't deal with the agravation with the current fad of "neck bushing" sizers for a SAAMI chambered rifle if they were selling at half price. A body die and a Lee Collet neck sizer takes care of my accuracy resizing work quite well.