Pro Tons of customization
Mutations are one of the biggest parts of Caves of Qud. Want to be a two-headed beguiling spider-thing? A four-armed flying plant-man? You can. There's also lots of armor, weapons, and equipment, which can be found enchanted, as well as a bunch of "spells" (mental mutations) and skills.
Con Can be difficult to get started
The beginning of the game explains little, depending on what attributes you put points into in character creation will have a high level of impact at the start of the game. This is not explained to the player, so if you do not put 18 points into "toughness" without having a very particular build in mind that will have some way of dodging or avoiding attacks, the result will just be plenty of death with little advancement.