After playing the Demo for most of the day, I played the Combine again, and right now I got to say I'm leaning more towards 2k10. It's a difference what all the little things make. Live 10 (based on the demo) needs A LOT of polish and refinement, where 2k10 a formula well established and just needs to be tweaked. All the stuff the Live guys put work into is revolutionary and definitely have raised the bar, but you got to meet the status quo in all the other areas first.
Unless Live has online franchise mode, I'm 85% sure I'm not getting Live this year...