When you do the quest a Deadra's Best Friend, you get 2 choices of getting the axe or the masque. What are the advantages and disadvantages of both items?
To start with, The Masque of Clavicus Vile is the true daedric artifact, and the only one of the two that counts towards the Oblivion Walker achievement. It also has one of the best benefits of any headgear for dealing with vendors.
The Rueful Axe on the other hand, is a two-handed battleaxe that may have a higher base damage than most of the weapons you can find/make depending on how early you do the quest. Unfortunately the enchantment on the axe is not particularly amazing (20 points of damage to stamina). The weapon has a speed of 0.5, which is slower than even warhammers.