Power I'm actually being a bit unreasonable. The matter of "better" is almost always subjective. I respect Uncharted enough to know it's a game to be reckoned with. Whether Mass Effect 3 or Uncharted 3 goes on to be considered the best game of this era..... it won't matter. What's more important is we got to play 2 amazing trilogies.
Uncharted reminds me of a badass action movie. Fun as hell and worth the price of admission but you forget about it shortly after. Mass Effect is an epic Sci Fi drama. Characters and relationships you won't be able to forget. It's really hard to compare an Action/Adventure to an RPG/Action game. One is super linear, the other is very open with thousands of decisions. I couldn't get too into Uncharted because it's not really my style of game and I'm sure many of you guys on here don't like Sci Fi and couldn't get into Mass Effect and I understand that.
Mass Effect uses a lot of believable and already studied sciences and physics. Also it's only like 150 years into the future so it's very cool to see what could be. I'm a science and Sci Fi junkie who just happens to love RPG's so this game caters to me. If you explore all the planets you'll see just how much detail Bioware put into this game. It's INCREDIBLE.
I'm also really stoked for Deus Ex BTW.
Edit: Damn just found this poll. Look how close it was. Mass Effect 2 52 percent, Uncharted 2 48 percent.