I wish it did tell you what was in it. I would have saved A LOT of money...
My take on these is that they are a half-price Doff pack with a chance for some bonuses tossed in.
Normal doff pack is 7 doffs, the three I opened gave me 4 or 5. Cost 125z compared to 275z. If I get a ship or anything else in the future, cool beans. If not, I still saved 150 zen.
I also got some fleet mark bonuses that are quite handy, and some Lobi crystals, but not enough to get anything good with yet. I have a temporal Doff mission I haven't used because I'm waiting until I get one more purple doff with the right skills to max my return on it.
If you buy them for the ships... well good luck to you.
But in general, if you look at the zen cost for the items in the box, even at the absolute worst yield on the drop table it is more than 125zen worth of stuff. Now, if none of that common stuff is what you want... then sell the keys for EC and buy the ship directly off the auction house. That's what I'm working on currently as I've got enough doffs for now so there's no good reason for me to open any more.
I reckon they are just about the best investment in dilithium for new/lower level players at the moment. They mostly seem to drop mini doff packs, but also some of the commodities which are hard to get from doff missions for level 50 players. I got a Science Vessel out of one (and possibly thats where my rubbish mirror universe ship came from as well?) so I struck lucky, but stuff like the temporal beacons sell for a pretty penny on the exchange as well.