I've had my 44" HF box for 5 years or so. I have plenty of room for the most part, but was never able to empty my older cheap Craftsman box.
I do need to reorganize both boxes, as I do have a lower drawer full of project parts. I have considered going back for the top box, but that won't fit under the shelf I built, and I keep considering the 7 drawer side cabinets too. Fully loaded the box moves easily around hen I need it to. And the drawers are solid and open easily. No detents though or latches.
I try to keep my SAE drive sockets on the left, Metric on the right. 1/2" Deep and regular at the back, and impact, 3/8" in front of that, and 1/4" in front. It would be nice if there was a second box length drawer, but the top one is plenty deep for almost any socket you may have.
When I bought this, I came close to getting the 56" box. Personally, I can't afford the Truck Tool brand boxes, I appreciate the extra depth of their boxes. But construction of the Harbor Freight boxes seems similar. Just no options for drawer arrangement like the like the Truck Tool brands. And of course, I bought mine the last year they had wrinkle paint finish. All boxes since then are glossy red...