Over the years I used shop benches, desks, cabinets with doors on top, and even a Workmate. Finally decided to build something specifically for my reloading.
Got a set to the NRMA plans that have been online for years. Built one that looks like this:
Instead of plain plywood I used 3/4" melamine coated HD particle board. Used birch plywood for the sliding doors.
This bench has my XL-650 mounted on one end and my Rock Crusher on the other.
The melamine is nice as it's easy to keep clean and you notice any powder grains that might have gone astray.
The entire bench assembly has enough storage room for my legal storage limit of 25,000 primers. Also room for a couple of 8# kegs of powder and another dozen or so one-pounders, depending on shape of container. Lots of room for brass and bullets. I keep 10-15 thousand bullets and an equal number of cases in storage both in the upper cabinet and lower shelf. ALL of my reloading tools have a home in one place.
Overall weight is sufficient that even though it is not attached to the building, I have it in an unused upstairs bedroom, it's stable enough that when I'm really rocking with the '650, the case feeder doesn't sway back and forth at all. Not even a fraction of an inch. The only way this bench could be more stable is if it was made of concrete.
As for "mobility", should I ever have to move it, the construction method provided in the plans allows it to be taken apart into three major components. Legs and lower shelf, Bench surface assy, and upper cabinet. Every assembly passes easily through a residential door. I built mine in my garage and moved it upstairs for assembly.
It all fits into a "footprint" of 3' X 6' 6".
I choose to stand while loading as the '650 is easier to operate that way. I tend to "batch" my operations. Every operation is performed on ALL cases before moving on to the next. When I start loading I load several thousand 9mm and .223 rounds. Precision Rifle rounds are loaded a couple hundred at a time (after individual loads are worked up).
This bench works well for my needs and the lower shelf is great to store filled 50 Cal ammo boxes.