SSS Owl is currently mid tier, despite it's high price.
SSS Owl is not best in any category, even though it's meant to be an end-game reward.
REQUIREMENTS 
25 eto kills - 500,000,000 YEN
SSS Owl (Even though it's based on Ukaku Kakuja) is out-ranged by the following quinques:
IXA (Gimmick)
Narukami (Gimmick)
Ginkui (Gimmick C)
SSS Owl has slow cooldowns, making every attack important to land. 
The Melee E does land a stun, but only for one movement (can stop a dash)
Melee R stuns both the user and the enemy, making the user vulnerable. (Bad for any type of combat) 
Ranged E can be jumped over, and overall useless unless used up close. (For a ranged move, attacking close is a bad idea.)
Ranged R has less range than Taki1 F. First  \stage fo Takizawa has more range than SSS Owl
Ranged F is inaccurate, and smaller than Eto shards. Making it nothing more than an area clearer, or a way to push people back (Even if used in this way, you can walk through the shards and be unaffected.)
SSS Owl is meta, compared to it's counterparts.