The choice rooms
There are two rooms and only one key. One key leads to 3-4 things for the player. The other leads to a single item contained in a chest?
The room with 3-4 things always seems like a pretty good deal, as opposed to choosing a chest. After all, how do I know that what is in the chest is worth as much or more than those 3-4 things?
Under what circumstances is it better to choose the mystery chest over the 3-4 rewards? Why would anyone choose the chest instead?
The chest in those rooms is always either a ring, an artifact, or a wand. It's often the better option.
Chest can frequently have rings and that kind of thing. I like rings, so I always pick the chest.
If my run desperately needs a healing potion or sorely lacks a remove curse scroll, I may opt for the knickknack side; otherwise, the sole mystery chest is what I typically choose as it pays off more in the long run.
I choose the chest if I don't have my loadout, consumables if I do (after blacksmith approx.)
I always go for the chest during early game when decent equipment is often needed, at that point most consumables are unidentified and a riskier bet, also there's a more limited space in the inventory
I always go for the chest except if in the endgame, and there's a transmutation scroll on it. I am rephrasing that. I always go for the scroll if it is the transmutation one, and in the end game, I don't really care about what to choose. But in the early game I pick the chest 100% of the time. A free ring / wand / artifact is always more handy than a potion of freezing, a potion of paralytic gas and a scroll of recharging.