What's best depends on your shop's floor.
My wood shop is in my two car garage, so my experience and suggestions are based on that. That's important because garage floors have two characteristics that I've found impact your choice in casters. First they're usually made of concrete and sloped towards the street to keep rain out, and second, they're usually not flat.
Everything in my shop is mobile in some way and I've tried a lot of different configurations trying to find the 'best' way to do it. What I've found is that there's no one answer for everything. If the equipment is large and heavy, having four swivel/locking casters isn't going to work because you won't be able to control it on a sloping floor. Also, on an uneven floor, most of the time it will wobble. Even if you lock all the casters, the fact that one or two of them won't be in good constant contact with the floor will cause your equipment to rock. I too just finished designing my router station based on the Incra LS system. I chose to make my own base. It's large and medium heavy. Here's what I ended up doing.
I chose to use two fixed 2.5" casters (woodcraft #152837) in the rear of the cabinet and two leveling feet (woodcraft #145840) in the front. Also in the front, I have a swivel, lift caster (woodcraft #158547) that you step down on to raise the front of the cabinet off it's feet for mobility around the garage. True, there is some mobility loss with the 3-wheel configuration, but I've found it easier to steer on a sloped floor. This configuration has other benefits:
- I don't have to walk around to all four wheels, unlocking them, to get mobility. I frequently have to park my equipment against a wall and reaching all four wheels is a hassle.
- the single centered lift caster allows me to raise the complete end of the cabinet at once. Some people suggest having a lift caster on each leg. As you go around raising/or lowering each leg one at a time, this tweaks and skews your cabinet out of shape as each leg is lifted until all four are up. After spending all that $$ on a precision Incra LS system, the last thing I want to do is bend my cabinet/top out of shape each time I move it.
- along this same thought, you want your cabinet sitting flat on the floor when you're not moving it. This is why I chose to put two leveling feet on the front. As mentioned before, on an uneven floor you'll typically have only three points touching (or two, if the floor is really bad) causing the cabinet/stand to rock. I can easily eliminate this rocking by adjusting one of the leveling feet. If the cabinet/stand is very heavy or very large, it might just conform to the uneven floor when lowered. It won't rock, but it also will be bent out of shape. Not the end of the world for an 7ft long workbench, but you wouldn't want your assembly table, jointer, CNC machine, router station etc possibly twisted out of alignment every time you move it.
- buy GOOD casters. I've done the budget caster from big box stores or online. They're ok when it doesn't matter and I've used them with on-and-off success. Then I purchased good expensive casters form Woodcraft and suddenly everything became easier. True, I paid for one of these what I could have purchased three of at Home Depot, but these caster have no side-to-side play! The cheap casters, even after locking them, your stand/cabinet will shift from side-to-side due to the 'play' in the casters themselves. Whether fixed or swivel, good casters should have NO play in them.
- Lastly, I did come up with a way to save some money. Woodcraft sells a workbench lift caster set (woodcraft #158547) with four casters for about $90. I bought these on sale some years ago (I think $70) for use on my shorter workbench. Since I only needed one lift caster for the router station, I didn't want the expense of buying a whole set. Then I saw they sell a 4-piece set, quick release plate (woodcraft #163735) or these lift casters for $30. The quick release allows you to easily remove the lift caster when not in use (stand/cabinet is in the lowered position). So my solution was to buy the quick release set, mount one on the router station and mount another on my short workbench in place of one of the lift casters. Now I can remove a lift caster and use it on multiple cabinets/stands. Eventually I may remove more lift casters from that workbench and replace them with quick release plates, freeing up more casters to use on other future projects requiring mobility. A $30 pack of quick release plates will handle four future projects, so that's not a bad price, and I should never again have to buy an expensive set of lift casters.
Hope this helps.