Battlefield 3 VS Assassin's Creed Revelations?

Hi,
Before I start I just want to let you know this is more like a general question, rather than a problem and I want to know the opinion of most hardcore gamers out there.

I have been looking forward to Assassin's Creed Revelations ALL YEAR, and since I currently own all AC PC versions (From AC1 to Brotherhood) I considered buying the collectors edition. But recently one of my friends showed me Battlefield 3. He pre-ordered the limited edition and I was able to check out some single player on his PC. When I went back home I torrented BF3 just to get a general idea of the game and to my surprise (considering I am actually a COD fan) the game was truly amazing. So far this is the only game on which I have been able to test out the true power of my 6970, running the game on Ultra with maximum motion blur and vsync turned on at an astonishingly impressive 45-30 FPS. I played the first few missions and now I really want to play the multiplayer as well. The problem is, if I buy BF3 I will be in no financial position to buy Assassin's Creed Revelations when it is released. This is a really weird problem because suddenly those "boring overused FPS's" seem interesting again and the unique AC series suddenly doesn't feel as awesome as it did during the first few showcase trailers.

So what do I do? Do I spend my insanely tiny gaming budget on yet another FPS even though I will probably get bored of it in about 5-6 months or do I strive towards AC:R, even though I've already been through 3 assassin's creed games and I know I shouldn't expect much from the fourth?

Share your opinions, and feel free to criticize my way of thinking.

I think if you will buy BF3 it will be a good decision as AC: Revelations will be released for PC in Dec if i'm not wrong. When it come's to Multiplayer the majority will vote for BF3 i think.. AC games are basically more focused on story and single player campain and i myself love the AC games and played all of them on PC and will get Revelations on PC as well but who knows you will buy BF3 for now and you will be getting AC:R in december as well and enjoy both games and their multiplayer modes :) you have a great monster card so enjoy the BF3 at it's peak

Thanks for the opinions you guys!

@Nem - I'm definitely not going to get MW3... I was disappointed by Black Ops and even though MW3 will be and InfinityWard game I still don't think it will be worth my time.
@boogieboy - I think I might actually do things the other way around - preorder an Animus (or Collectors) Edition of AC:R and buy Battlefield 3 cheaply off of eBay in the early months of 2012. I loved (and am still playing) the AC:B Multiplayer and I find it very addiciting. I'm maximum level, but I just play for the fun of it. Here's hoping the AC:R Multiplayer will be just as good.

Anyway, I still want to hear more opinions! If there's anyone here who has played the AC:R multiplayer demo I would LOVE to hear some opinions... Anyone