I will always lean hard towards Sony most and Nintendo second, but I bought a 360 and owned it for half of this gen. Besides having to send in a RROD unit for repair (which was a painless, free 30 day process), I loved the system and had a blast playing it.
MS hasn't done anything yet to sell me. My launch PS4 has been reserved on Amazon. Everything I've seen from them since their announce, while a clusterfuck, has generally been moving in a positive direction. Just keep showing me more games like DR3, MS. At some point, I will probably be plopping money down for one. Especially since I have yet to experience Kinect (and 2.0 looks a shit ton better than 1.0).
The devkit/debugging bit is exciting because it will hopefully result in more polished games launching.