Ok this thread makes no sense
a) They are completely different games and offer different experiences
b) as someone previously stated there is no actual demo of Halo 4
But I will say that although I own every Halo game and Both Mass Effect games I am way more excited to Play ME3 maionly for the insane story and the choices you get to make and the multiple playthroughs that I will take through it.
But I am still looking forward to H4