I have a strong mount, but have not put it on the Dillon yet. You will need it if you want to attach a bullet tray. Some extra stuff that Dillon sells, attach to the Strong mount itself, and not to the actual press.
Another option; I use a welded T shaped plate with the press mounted to the horizontal and the vertical mounted in a vice. It gives me the height advantages of the Strong Mount but with quick dismount and rotation capabilities of a vice.
I use a strong mount. Without it I had to mount the press on the edge of my workbench. Pulling the handle down with vigor caused the bench to rock because the vector of force tips the bench forward. Although I could have anchored my bench to the floor or wall, I chose to mount the press farther back on the bench top, so the force of pulling the handle went into the front legs of my bench. The added bonus is being able to use the bullet tray.
I don't think the strong mount is necessary, but it's a worthwhile purchase. Check out ebay, there's a guy making knockoff strong mounts that are equal to or better than the real thing. They're also a bit less money.
I have a 550 without a strong mount on my bench. I operate it while sitting on a drafting stool. The 650 I have is mounted on the same bench utilizing the strong mount. I operate the 650 while standing. Both configurations work well for me.
I use the strong mounts on each of 4 presses. The mounts are my quick change feature. I clamp or bolt the mount to the bench as needed. The off duty presses stand at ease in the corner on their own legs.
