I have recently added a 2019 CB500X to the garage, and some have asked how does it compare to the 310 GS.
For 2019, the CB500X was updated with a 19" front wheel and longer suspension travel over the earlier models. I find them very similar in ergonomics, seat height riding position etc, both present similar levels of riding comfort. The CB500X does have little better weather protection. Seat of the pants performance difference is not huge.
The reality is that they actually present the same bang for buck, where I am (AU) the CB500X is approx 20% more expensive taking into account that it does not come with a rear rack or bash plate but does have LED lights. The CB500X is ~20% more bike.
Better highway experience, bigger engine less stressed and more economical at 110kph (70mph).
Standard LED lighting
Bigger range with 17.5l tank
Better clutch package (Slipper)
What's much the same
Good on road handling
<90kph fuel consumption
Off road capability
Ergonomics and long distance comfort
If considering both bikes, suggest you ride them both and decide which best suits your use case and budget. Bottom line they are both great lite off road adventure options.
Seeing as I also had one for a while, pros cons for the CB500X to a 650 Vstrom
20 Kgs lighter
No top heaviness
Better off road capability
Less weather protection