Ok since Red Ginger was my first Rainbow on Nutaku (paid) and my first Rainbow on DMM (free) this vote might be a wall of text.
Stats: Her HP is amazing which complements one part of her moveset rather nicely (Her Skill absorbs HP), Her Atk is pitiful for a 6* (there are even 5* with more Atk), her Defense is average for a 6* (there are a lot of 6* with such a defense). Sadly her lower defense doesn't help her Counter Ability and of all the Counter Girls she might have the weakest Defense Stat and the weakest Counter Damage.
Verdict: C
Skill Activation Chance and Skill Damage: 26 % Skill Activation on Level 1 and 36% Skill Activation on Level 5 is really n1. Most Rainbows have a Skill Activation Chance of 24 % on Level 1 and only 34% on Level 5. She deals 4,3 Damage to one enemy. Not that impressive due to the fact that there are other Single Target Nukers which can inflict x4,8 - x5,2 damage to one enemy. However most of them don't have HP Absorb. HP Absorb really helps her Counter Ability. I will cover this in the Ability Section.
Verdict: This section is fantastic. S
Abilities: Well in my opinion there is everything represented in this category. The good, the bad and the amazing.
Thanks to her recent Buff she increases Attack for party members by 30 %. Not the highest group atk. buff but definetely a good one.
Increases Skill Activation for party members by 1,28-1,36x based on ones own Skill Level (1-5). Obviously you have to invest Skill Blooms to get to the 1,36 multiplier. Is it worth it? HECK YES!!! If you want to boost your consistency in first turn squads, if you want to buff your overall damage output this ability is amazing and makes it so much easier for your knights to activate their skills reliably. My Maple has 5 Skill Levels and let me tell you this Ability is amazing and rare.
Increases Damage of Skills for party members by 15%. It's a n1 recent damage buff. A little unoriginal but solid.
Adds 150 to the party's speed. So this is where it gets a little bit annoying for me. I hate this Ability. Once upon a time we all wanted one fast Squad for specific Events. I called it the Speed Meta. That was long before Bloomed Forms even existed. Today Event maps are homogenized and you don't need one fast Squad anymore. This ability cripples Team Building in my opinion cause you have to adjust all other teams to the speed difference this Ability creates. Yes you could argue that you can farm faster with that Speed Boost but let's be honest: Does it really matter if you do your daily FKG routine in 15 or 30 minutes??? Decide for yourself.
Counters 100 % of the time using 3,75 % of your defense as attack power or Super Counters. A good Ability but sadly her Counter Damage is on the lower side and there are a lot of girls which outclass her in pure Counter Damage. However due to her amazing HP Absorb she'll be able to survive on harder maps for a much longer time period compared to most other Counter Girls and that's why that Ability Combination is so good.
Verdict: I have seen other Ability Combinations which are even better but her Abilities are amazing overall. A
Teambuilding Options: Due to her wide range of Abilities you can put Red Ginger in a lot of teams and she will do her job fine. She is a good Allrounder in my opinion. A Jack of all Traits, a master of none. A n1 Support Unit. She won't dish out the most damage in Counter Teams. Saffron will. She won't dish out the most damage in Skill Damage Teams. Maple will. But she is a n1 addition to a lot of archetypes and will do her job fine.
Archetypes where she is good in: 70 % Debuff with her as Life Leech/Counter Unit, Skill Damage Teams, First Turn Squads, Teams which utilize Abilities like this: Increases Attack for party members by 120% of the party's speed.
Conclusion: She served me well in the past. She was my first Rainbow on both versions. She helped me quite a bit in the Speed Meta of old days and she also helped in the beginning of my DMM journey. Lately she has fallen a little bit out of flavour for me. I have difficulties including her in my top 20 due to her Speed Ability.
Red Ginger is a n1 Unit with a wide range of Abilites. She is versatile and that's her biggest strength in my opinion. Team Building can be difficult due to her Speed Boosting Ability so beware of that. I don't think she is suited for S-Tier (she lacks god-like stats and she also isn't as tanky as Kerria or Saffron cause she lacks Evade). I have to disagree with Shad here. I don't think she comes close to the brokeness of Kerria or Saffron.
Final Verdict: I wavered between A and a really good B+ (mainly because of her Speed Ability. Yes it's that annoying for me) for a long time. In the end i decided to go with A-Tier