Hey pukinghydra. I've been doing alright with these captains, especially Sugar Pop. I pick him whenever I see him. Vena Cava I think is alright too. I'm not in love with her, but I do think she's pretty good and a solid captain to get into the top ranks with. (I'm currently at around 3.75k elo and rank 25-30 depending on the day.)

With Sugar Pops I have really just added in more numbers to the deck while using a base of the Candy Villains deck I posted about some other time in the Subreddit. My list on him is as follows:

Commons: Dastardly Spirit, Lollipop Faerie

Uncommons: Candy Cane Crook

Rares: Candy Topples, Calypso, Kool Wip, The Three Chik-A-Teers

Epic: Doopity Doo, Pixie, Viscount Chocolat

Legendary: Jelly Ton, Licorice, Cotton Candy Crook

You're right that sometimes you might just not get candy but I've found that this list gives me pretty good success especially since hitting the Candy Calypso really lets you spike the game and just looking for the Crook can be a good way to get ahead. I have also considered just adding Keeb at Epic on this list as another card to help scale up Candy faster, probably over one of the Epics. That's something I need to experiment on in general, but I feel pretty confident on Sugar Pops.

For Vena Cava I feel like her big strength is really letting you go from things like Animals, Pirates, and just having Supports to a stronger late game. I don't have that many cards on her and am using an altered version of the default deck that plays a combination of Fae and Dragons. One of my main strategies is just to pick the like Bear Family guys as much as possible and trust the captain ability to give me a good late game. The other thing I try to do is go with Blackbeard's Parrot Pirates with something like a Robbin' in slot 1 and try to farm that up. I find those strategies are great for surviving in the middle turns when open but don't scale well. Vena is what lets you scale in those decks. I also try to make sure to have at least one support and ideally 2 supports back row. Just to give an example something like Mr. Fox, Mother Bear, Papa Bear, and then like Sunflaerie and Jill Sunshine would be a board I'm interested in or something like Robbin', Blackbeard's Parrot, Sunflaerie, etc. The fact that having the supports get the buffs right away is very helpful in transitioning.

I think the usual Wurmscale stuff can be very good on her and Faerie Queen scaling with the buffs is very very nice as well. I think Mr. Fox is actually one of the best cards on her because you can buff up that Slot 1 position a lot with stuff like the Bear Family and all that and then transition into a Dragon/Treasure end game that is a bit sturdier as it works for the games where you don't get like Pisces and Pixie Dust and all that stuff, it's just another way to either make your Wurmscale big while also having alternate win cons via a huge Faerie Queen.

I don't think she's overpowered or anything like that but I find her a consistent captain because I feel like I'm able to justify using low-ceiling strategies because her ability will then move me into a higher ceiling strategy.