This tool box has a surprisingly well thought out design. (EDIT: This actually isn't all that surprising. I subsequently found out that this tool box is a rip off of the Beta C20 tool box. If authenticity matters to you, you should look at the C20 at four times the cost. The C20 is also available at Amazon.) You push down on the handle to open up the "butterfly", and pull up on the handle to close the "butterfly." This is a natural motion as you generally set the tool box down when you begin working, and then pick it back up when you're done. This would be less convenient if you were working on a ladder with the tool box above you on a ledge. (This is somewhat less likely, but not entirely impossible.)
You can open up either side independently by tilting the handle in that direction. This actually works out to be a bit of a negative as the butterfly doesn't open smoothly unless you manage to push the handle exactly straight down. If you're off to one side by even a centimeter, that side opens first, and then you need to force the handle in the other direction. What should be one smooth motion generally ends up being two distinct motions. It's a minor nuisance, but one I've quickly gotten used to.
The four trays are not huge, but I find their space to be ample. They are easily tall enough to swallow a complete socket set, though you'd have to lay deep well sockets on their side. I use the middle trays to organize my metric and SAE wrenches, and unless your wrench collection is larger than 12 per type, I think you'd find the space sufficient. Somewhat less sufficient is the access opening on the middle tier of trays. It's not hard to pull a tool out of them, but it is hard to find a tool in them. I generally end up removing every tool searching for the one I want. This may prove to be a big deal in the future, but I haven't grown entirely annoyed with it yet. This is still a large improvement from my previous toolbox where _every_ wrench was mixed in one giant compartment, so I ended up going through every wrench anyway. With my new organization, I'm only going through half of the wrenches every time. I suppose you can call that progress.
The bottom compartment is one large, undivided compartment, and is easily large enough to swallow my other assorted tools that don't have a neat category to fall into.
I very much appreciate this tool box's size, weight, build quality, and price. I think that the manufacturer managed to hit just the right balance amongst those features. The tool box is well constructed, and if there are any issues, it would probably be in the butterfly hinges. I haven't had the tool box long enough to say this definitively, but the rivets look and feel fairly strong, so I don't anticipate any problems there. The only disappointment I've found is that the tool box was made in China. (Incidentally, the original Beta C20 tool box is also made in China.) This information wasn't available until after I had received the tool box, and might have influenced my decision had I known about this before the fact. Regardless, I'm pleased enough with the tool box to keep it.