I believe to go with both, unless one feels the price of either is going to drop soon.  In that case, go with the one that ISN'T going to drop in price.  If need be, hold purchasing for a few additional weeks.  I would tackle Bioshock and beat it first, then move on to Mass Effect.

Mass Effect.

If you're going for all the stuff, you'll probably get more playtime out of it.

I'd go with Mass Effect.

I've heard good things about both but more so with Mass Effect. That's just someone elses opinion though. I haven't played either.

Edit: Seems pretty close with the users posting in this thread.

Mass Effect.

LEFT 4 DEAD you wally!!

but seriously out of those 2, Bioshock gets my vote :)

Out of those 2 I would have to go with Mass Effect. It is really a great game and you can play through different times to come up with different endings.

Go check out the demo for Bioshock and see if you like it, it is a good game as well. You may fall in love with it and if that happens go with that.

I'd personally suggest Mass Effect, truly an epic game.

Mass Effect.





The d21 has spoken.

I'd go with the choice that gives you the higher Gameplay hours to price ratio. I've heard Bioshock was relatively short as compared to Mass Effect(I might be wrong on that, I'm not 360) so Mass Effect might just give you more filling gaming experience, even if Bioshock might end up being a tastier one.

Eventually you're going to want to play both since they're both amazing games. At that price though Mass Effect is a steal so I'd get it first.