At the end of "A Daedra's Best Friend" quest you get the choice of getting the rueful axe (20 stamina damage) or Clavicus Vile's Masque (Prices are 20% better +10 Speechcraft, Magicka Regenerates 5% faster). Which one did you get?

I got the masque because I liked the boost in prices and the +10 speechcraft. Barbas, though irritating as hell, was a good companion because he distracted enemies while Faendal and I picked them off.

For the current character, it'll probably be the Masque.

Rueful Axe isn't even that great. A glass battleaxe with damage stamina? I can make a better weapon.

In Oblivion, keeping Umbra was horrendously worthwhile.

The Masque. The Axe was a really crappy weapon, plus my character doesn't even use axes. If it had been something else I might have given it more thought but as it is I immediately chose the Masque because only the Masque qualifies as a Daedric Artifact for the Oblivion Walker achievement as well.

The Mask for me.

I honestly saw no reason to choose the axe. I don't remember its exact stats, but as already stated here I remember it being weak and IMO no match for the mask.

The Mask, but I didn't really use it since I had Volsung by the time I got it.

By the end of that quest I was so sick of that yapping piece of festering [oh, man, don't let your momma know you know words like that] that I wanted to gag the yap-machine and slowly roast him in as painfully a fashion as I could dream up. Stone dog that never makes another sound? Yeah, that's worth a sadistic mass murderer Daedra on the loose imho.

Now, if I coulda used the axe to split the mutt's skull...that'd have been a different matter.

Both items are pretty useless. If I have to decide based on the looks, I'd keep the axe.

Don't feel sorry for Barbas. Clavicus Vile is a sort of Schizophrenic whose split personalitites have two distinct appearances: the man and the dog. By killing Barbas, you basically make Clabvicus Vile stronger for a few centuries (until the split personalities emerge again).

I kept the mask. Barbas was cool and helped a lot before I gave him back. I use the mask too, it looks mean

The Mask. Both items are not very useful for combat, but at least the Mask helps you in town. Also, the axe doesn't count towards the daedric artifacts count for the achievement.

I stupidly took the axe. I was going for the Oblivion Walker achievement...my mistake.

You technically dont have to take the mask to finish out the achivement but you do then need to do all the other Daedric quests since you need 15 for achivement and there are only 16 quests.

I took the ax not knowing about the mask. Was there a clue that there was something else if you didn't take the as, or did everyone read the book/wiki beforehand?

I know that now. http://www.gamesas.com/index.php?/topic/1314158-oblivion-walker-achievement/page__p__19760206#entry19760206