I've mentioned this before, but - if you can only really afford to pull in a Birthday Nightmare in one of the two games (whether those reasons are actual money/finances or in-game resources like DV or DP) then it's better to pull in the original game.
In Nightbringer, the odds of pulling a Birthday UR are 0.49%
While in the original Obey Me, the odds are 1.00%
So, the chances are basically doubled for your pulls in the original game.
The Birthday Nightmares in the original Obey Me will have far fewer possible URs (usually only the Birthday UR card, that character's Chapter A UR card, and at least one UR card from past banners) at around 3-4 in total.
This is because the Birthday Nightmares in Nightbringer have a dozen other possible UR cards in the pool (all 12 of the UR cards from the Chapter A banner) so the odds have been adjusted for that accordingly. There are 13 possible UR cards you can pull (the 12 regular URs + the Birthday UR) so the odds are different compared to the original game to reflect that.
So if you can only pull for a Birthday UR in one game, your odds are better in the original OM, plus there's a chance you could pull old UR cards from past events that are no longer obtainable which is invaluable now that they've stopped doing Nightmare Revivals.
Nightbringer has a lot more UR cards that are possible to pull - I pulled at least five URs (Lucifer, Mammon, Barbatos, Beelzebub, and Diavolo's non-birthday UR card) while pulling for Diavolo's new Birthday UR in Nightbringer - which could be more appealing to you.... especially if, like me, you already own all the other older legacy cards in the original OM pool. However, the odds for URs are lower overall to make up for this. Plus, the other 12 URs are still available through Chapter A, including your free pulls, at all other times outside of character birthdays. In comparison, the old cards in the original OM are unobtainable outside of these Birthday Nightmares.
From where I'm standing, it's a better option to pull in the original Obey Me, in almost every way. Your odds of pulling the Birthday UR card are doubled, and the other UR cards in the pool are not easily obtainable through Chapter A like they are in Nightbringer.
In the end, the choice is yours. I know that many people have stopped playing the original game since Nightbringer came out and that's valid, especially if playing both games at the same time is unrealistic for you. So this all depends on what makes the most sense for you and what would benefit you more. The odds of pulling the Birthday UR are higher in the original game, but there are more UR cards to possibly obtain in Nightbringer. So if you can't pull in both games, make a decision that works best for you ☆
Idk how lucky this is but it feels really lucky to get both Awakened Pure Vanilla and Shadow Milk in the same 10 gacha pulls (this was with the awakened gacha thingy that you need special cards to get, but still!)
Also the beasts seem to really like me, since I’ve pulled 3 of them through normal gacha
And like, I got eternal sugar through her dedicated Gacha, I think it was before 100 pulls too which I know is really lucky, and I also got both Shadow Milk and Mystic Flour through the normal gacha odds.
I’m not bragging, I’m just really confused on my luck since I’ve only started playing this month.
In case you're wondering why you didn't get URs from the 50 free pulls we just got on chapter M:
They're still at their original rates, which means you have a combined 1% chance to pull a UR card on chapter M. Chapter A is 0.25% on each card (combined 3%) and new event gachas are at 1.5% per UR (3%).
Don't get your hopes up - it's nice that they gave us free pulls randomly but don't be too discouraged if you get nothing but SSRs.