Inconsistent documentation + issue running ROS Melodic on Ubuntu 18.04

I am having a bit of trouble running PX4 SITL using Gazebo and ROS. I am wondering whether I should use Ubuntu 16.04 + ROS Kinetic or Ubuntu 18.04 + ROS Melodic, as I am not sure which combination is currently supported/works best.

From the dev documentation, it seems like the second option is recommended as the install script installs Melodic. However, the documentation on ROS says this script should actually install Kinetic. Maybe the doc just needs to be updated?

Anyway, right now I am trying to run a Gazebo simulation using roslaunch mavros px4.launch, but the process hangs at [ INFO] [1558880500.575509173]: MAVROS started. MY ID 1.240, TARGET ID 1.1. I am wondering if switching to Ubuntu 16.04 and ROS Kinetic could help solve the problem.