It depends heavily on the kind of fish you are playing. In a deck with 4 null rods, 5 strip lands, daze and spell pierce, stifle is better than in aggresive decks with less mana denial. But in general it has become worse since Fish and Mud have become more popular, and there are few storm decks now.
Avoiding 1 oath activation is not great unless you already have some beaters in play (excuse me, in the battlefield :p), having 1 counter for oath or 1 bouncer seems better. You can similarly avoid one Time vault activation or tezzeret, but it is not great since rod decks haven't explosive wins.
IMHO now is better to have spell pierce/snare maindeck in front of Stifle, and Annul in the SB for Mud/Oath, usually the worst pairings besides Ichorid.
To nitpick, I would disagree that a bouncer is better than Stifle. Terastodon and Iona cause a lot of damage upon entering the battlefield, and the graveyard is a valuable resource that potentially builds a lot upon Oath's resolution.