I am one of the OS developers for a military vehicle that utilizes vxWorks and Linux. It's honestly no different than other OS work out there. Documentation and help outside of WindRiver's official docs are more scarce, and open source support is smaller, but grasping how an RTOS works vs a GPOS isn't any major mental leap. If you can program in C and understand communication protocols like i2c, UART, SPI, CAN, etc. then it's not terrible.
Right now, we are looking at moving away from vxWorks and onto a Yocto-built Linux with the RT patches to the scheduler. From a requirements standpoint, the RT patches meet our needs for "real time" since our timings require more of a soft real time than a hard one. There's also way more support out there for Linux, and I am also slightly biased in that I am more of a Linux guy than a vxWorks guy simply due to familiarity and ease of troubleshooting.
This latest news with vxWorks is great, however. I actually sent this to management because we are attempting to figure out what direction to take as our current version is reaching EOL.