It looks like they are really close, the Phantom 3 now only offers their own camera’s and gimbals, and doesn’t provide HDMI from the controller but has a longer range (1.2 mi). They have two models the professional (4k) and advanced (1080p). They have included the lightbridge technology (HD videotransmission) into the P3. While the SOLO has HDMI, reduced range (0.5 mi), external gimbal and cameras (GoPro). The SOLO ends up being more expensive, has a PIXHawk autopilot (compared to NAZA) and 1 GHz computers in both the drone and the controller, also has an expansion port, and is open source.
Both of them should be out by the end of May, 2015, and we should expect more videos and hands on tests by then.