Darth Vader:
I've had quite a time during my runs with him, I only have a decent Kabal right now that I will use for teh lulz opportunities, but never as a serious character of mine.
I like to play him zoning, but when it's time to get up close, I do little NDC pressuring and more Buzzsaw/Tornado Slam 50/50 mixups. When I get the chance, I'm going to develop a gimmicky Kabal; a bit similarly to CSZ, with gimmicky techniques that'll no doubt catch people off-guard and allow me to win because they'll be thinking that no self-respecting Kabal player would use gimmick-tactics.
Jade:
So fun to play as, but difficult to get well with. Been 7 days since being given Jade, but I'm technically only on day 4, since there were days I didn't play MK or the PS3 at all. I plan to keep Jade in my small array of fighters because she is fun, and I have no female characters in my array.
Still developing my game with Jade; currently getting a better grasp of spacing, footsies, and the long-ranged normals for whiff punishing. Also experimenting with the mighty Glow.
I don't think I have a clear favorite TYM-given main, they both have their ups and downs.