User blog comment:Crimson Storm Mich/Future Units Preview v2/@comment-32064901-20170525131419/@comment-31168242-20170525144252

The current Omni tiers:

cost 45=starter units and event units (can cover specific buffs that are missing from squad, none break ATK Parameter cap, most people prefer not to use) <  cost 47= Legacy omni unit, Ark (light), RS 7 star LV.1 (Some are very versatile, few break can break Atk parameter cap, one certain units provide EXP boost) > or < cost 48 RS 7 star LV.2 ( always provides good buffs but none break atk cap, can sometimes be outclased by Legacy omni, 2 units provide exp buff) < Cost 50= RS 7 star LV.3 ( best units you can summon from RS gate, nearly all of them break atk cap. can cover up to 1-3 unit roles in squads, one of them boosts exp) < cost 54= strategy zone and FH rank 90-100 ( the units you atually have to work for, might be the best units to have in BF, Nearly all of them break Atk cap, Owen in particular breaks the atk cap even more going up to a 150,000 damage)

This is how I believe you should rate your units.