This is the perfect workbench for my needs.
I upgraded the casters to bigger ones as my shop's floor is in rough shape.
I also added storage under the two work surface next to the miter saw. This was just a matter of closing under the 2X4 frame and making the two sections on casters a little shorter. The only downside for that mod is that the plywood can bend a bit since it is not screwed to the frame. I don't mind since it falls flat as soon as there is weight on it. Also, this mod makes it hard to include fence system (it would need to be removable, like fixed with dowels only, no glue) and almost impossible to include a precise fence system since it would need to be removable. In my case, I do rough, non-repetitive cuts, so there is no need.
TIP : Pay a little extra for smooth plywood. I lost a lot of time sanding mine :(