As a big Painwheel fan, I can't wait to finally pull Biting Cold. She looks like second best Gold PW for me and just slightly below Buzzkill.
On offence:
+ She is a Painwheel. Even though her damage is rather low for a Panwheel, it's still pretty high. Plus bleeds from Death Crawl and Cruel Lily.
+ "No Revival" is just great. Many defence strategies abuse Fighter revival (Plot Twisted, Last Hope, Kill Joy, etc.), go laugh at them!
+ Meter Gain on kill is great. Finish the first opponent with a BB3 - have another one half ready!
+ Take the first opponent down in the right corner and stay there - you will have stacks of Barrier and Regen that will keep you alive if you make a mistake.
- Damage is still lower than that of Buzzkill or Raw Nerv. SA does not help with damage.
On defence:
+ Barrier helps to stay alive, Thorns punish attackers. Add Grudge on top of that and you have potentially the most sturdy Carol in the game.
+ Water element. Works perfectly with Frost Armor catalyst , so meta. Add Thorns on top of Frost Armor damage reflection, Grudge to provide more Armor
+ Pair her with Dead Alive Squigly for Last Stand (and get Barrier during this Last Stand, so you would not be killed immediately after Last Stand expires). Synergies galore!
- She does not combine well with other Painwheels on defence. Buzz goes with Fly Trap, Evergreen Evil, and Gone with the Wind catalyst. Neuro+Freaky+Nerv+Darknut+Tainted Blood=Very uncomfortable. Biting+Twisted Mettle?.. Meh.
- Shines only in multi-Fighter nodes as she needs a corpse to feed.
Considering all this, I would absolutely Diamond her for Rifts, not that sure for Prize Fights (but let's see what Diamond PFs bring to the table).