I have a stage Krieg who's build is abit between powerhealing and damaging.
I maxed hp recovery AND rebirth revival AND revival.
This ensures that I have 3 heals to deal with in the event the party lacks an Eir ( which is like 90% of the time ).
Speaking of Hp cost for hp-recovery, I feel that if you are good enough, you can simply chuck a true revival in when your hp is 0, instead of hp-recovery.
Hp recovery to me would be Eir's sunlight of healing but with 30s cooldown.
30s isnt alot, unless you're talking about a team of LIMES which I had a hard time with. And, it's faster than Sunlight of Healing. Also with a whopping 100 range. Cool to max, or leaving it at 1. But 0 is a no-no.
True revival can be maxed, its there for myth lol.
Next, revival can be left at 1 to fake-ress, or maximise the effect at max after clearing a miniboss(es). No problem, except its harder to aim.
Okay, heres my veridict on Comet VS SuperStrength.
Comet: can air-combo.
SS: Ground type, can't air combo EASILY.
Comet: 15s cd.
SS: 30s cd.
SS deals slightly more damage than Comet.
Range of effect
Comet: Semi-circle in front of Krieg
SS: All around the radius + abit of range of Krieg
Comet: Easily dashable after attack
SS: Cannot dash cancel, leaves Krieg vulnerable to attacks for 1 second( 1 second is enough)
Comet needs less MP than Super Strength.
Summary on heal
Add what you like, but if you go my way nothing would go wrong, I'm sure.
Summary on C VS SS
I would say Comet owns SS, due to its versatility. (combo, dash away, lesser mp consumption). But SS would be better for dispersing lackeys which are scattered.