D5200 Pros: - Very slightly better low light performance. - Higher resolution. - Light weight. - Articulated display. - Better video modes. - Mounts pre-AI lenses (read: very old manual focus).
D7000 Pros: - More physical control points, including a sub command dial. - Magnesium body (D5200 is plastic). - Some weather sealing. - AF fine tuning. - Metering with manual focus lenses. - Optional battery grip. - Longer battery life. - Higher speed continuous drive. - Deeper effective buffer (smaller file size). - Dual SD card slots. - Can autofocus with all AF lenses, not just AF-S.
My answer: a D7000 wins, for now. The next generation D7x00 series will I'm sure be still better, but it's not out yet.