I've gotten a few of these. It has always been worth it. But know that it is possible that you might get things that aren't useful for you specifically. Example: one of them had a pair of VERY snazzy pants designed for hardcore hiking, in a size nowhere near what I could wear. I got lucky on that as it was a size my wife could wear. I have gotten a set of keycaps, which seem nice enough but are in a color I wouldn't want to use. Those will likely collect dust until I find someone who would want them. That's just the nature of the beast with random boxes though. You might not get anything that YOU have a use for. I buy these for gifting options. For that, they work splendidly. As with many things, just know what you're paying for and set expectations appropriately. I've gotten some insanely nice stuff from these and have no complaints on the value.
Mishmash things, some more useful than others. A pocket knife, paring knife, pen, fabric, sneakers, among some other things. If you like to gamble this may be up your alley.
Useful stuff I got was a 9" kitchen knife, Etymotic IEMs.
Stocking stuffers for friends: titanium emergency whistle and firestarter.
Kinda meh: some japanese textile sampler pack, women's wool pants
I got this just for the fun of the surprise, and it didn't disappoint!
I know that I got lucky but it had 2 items that each were almost the cost of the whole box, and a lot of smaller value items that added up quickly. A few quick google searches and some back of an envelope math tells me that we came out WAY ahead as far as the price is concerned.
I would not recommend if you are expecting anything out of it, as there isn't a theme or any indication of what you will get out of the box.
BUT, if you just want to roll the dice and try to get something amazing this is an 11/10 in my book!