They work fine and can carry a large of amount of flies. The midge box has magnets and is handy for not losing flies.
Are those silicone inserts on the 2nd box?
I use the magnetic fly box pictured on the left exclusively for my midge and nymph collections. Mine have another row though(18 sections). They work great. I like them because they are really thin which helps reduce the bulkiness while in they're in my hip/chest pack, vest pockets, or in my float tube and Kayak compartments. The only downside is that the locking clamps don't have much friction between them so they are prone to open when you don't want them to. I own 6 and about half of them have this problem. It's probably the 3 no name brand cases I bought online. I just keep a rubber band around them just in case. The clear view cover is made of soft plastic and is also prone to get scuffed up after awhile if that matters to you. All in all they serve a purpose for me and I like them.
One word of advice though....If you buy one, don't leave it exposed to the Sun in your car. The magnetic sheet on the bottom will start to bubble up and get warped. I just this the hard way when I left one on my seat while tubing at Crowley.