Gifts of winter vs Winter's envoy

Tharja And lissa have uniques B skills, not to mentioned tharjas A.

The other banner summon has a better armor Robin.

What do you want?

Okay. Let's talk Fodderability, and then usability.
Now, Fodderability. (Only skills that aren't found on 4 stars easily)

Gifts of Winter has Bold Fighter, Vengeful Fighter, Atk/Def Solo, Close Guard, Atk Opening , Joyous Lantern, Glittering Breath, and Dazzling Staff.

Winters Envoy has Vengeful Fighter, Bold Fighter, Handbell, Sack of Gifts, Candelabra, Close Counter, Armor March, Tannenboom.

Aside from unique weapons, and Close Counter which depends on if you even want to use units that require it, you would prefer to pull int he Gifts of Winter for Fodder alone since you can get Both Venge, and Bold fighters, with better and less specialized skills.

Units(Usability)

Winter Ephraim, Winter Fae, Winter Eirika

Winter Chrom, Winter Lissa, Winter Tharja, Winter Robin

Winter Eph is the hardest hitting unit ingame as of this current moment, and comes with an entire setup that can have him KOing the entire game from the get go. If you want somebody who will hit like a truck, literally, then go for Ephraim.

Winter Eirika is our first armor healer. She can give your hard hitters more Atk, and even work as close counter tank due to her defenses. Aside from her offenses, she's the best support unit for armor teams, if you use them alot, go for her.

Winter Fae is the best mixed tank in game, in she's extremely good at what she does. High Res, Def and her weapon makes her even harder to kill. If you want to be able to take on mages and melee and score well while you're at it, then I recommend going for her. Also the easiest to get since greens are more likely.

Winter Robin is a good unit, but he's plagued by a need of a few specific skills. He can run Vengeful Fighter which will deny enemy doubles due to speed and allow him to double. Bold is great, but that neuters his speed, and Wary destroys anything he had in spd advantage. As such Special Fighter is the best for him but it's hard to get and as such, unless you truly wish to build him, he's borderline hard to build thanks to his once more strange stat mix for an armor. Aim for him if you want a unique speedy armor unit.

Winter Tharja was our first tome armored unit, and she still holds the title well. Her ability to tank hits via her high defenses still holds true. However, her speed is horrendous, and she can't be used for offense at all since her speed is low as it can get. Aim for her if you want a really good tome armor unit.

Winter Chrom is the first iteration of a Surtr type stat line in the game, and is extremely tanky and hard to kill. However if you wish for an insane tank, realistically speaking a Sheena could serve you just as well, just saying. Aim for him if you want a physical tank (I'd recommend just saving for Surtr someday if that's the case)

Winter Lissa is relatively underrated. She can perform her offense well, but she performs better in defense due to her excellent mixed defenses. She is one of the strongest armor units for Vengeful fighter, and a great pull if you're looking for a great all rounder.

TLDR; Fodderability(aside from Close Counter) and Unit Consistency goes to Gifts of Winter

Gifts of winter units are pretty good but the fodder in winter envoy is a tad better. The only problem is one is a 4 hero banner, not as good as a 3 hero banner in terms of summoning rates. If you need exclusive skills or like armor then envoy might be good in the long run. Just be aware the banner is out for a month, plenty of time to decide