I'm sticking with the 360 for right now because there's no real games that interest me yet on the X1 aside from games that are also on the 360 (I will admit, I've been holding out on buying Battlefield 4 simply because I can't pass up 64-player battles on XBL, but that game's not a must-have for me)...I'll probably make the "switch" (I say that in quotes because I'll probably still be playing my 360 as well for another few years until the X1 has enough games) around January or February of 2014
not changing this sig until i feel like it - started 6.23.2009
Lots of reasons for me - potential hardware issues, lack of games, a sizable current backlog and a lot of upcoming games to look forward on the 360/PS3, but I suppose the biggest one is the cost, neither console represents good value for money for me at the moment. I've also got a Wii U and a fairly up-to-date PC to keep me occupied as well.
I'll get both the Xbox One and PS4 eventually, I'll decide which one to get first when I'm ready to part with my money.