A minor annoyance to me in SpaceEngine is how the planetary mass display gives the mass of some ice giants in Earth masses and some in Jupiter masses. All the rocky planets use Earth masses and the gas giants use Jupiter masses, and this is fine, but the ice giants are tough to compare in mass because of the switch to Jupiter masses halfway through their ranks (I think it's at 20 Earth masses). My suggestion is that the point where the unit is switched from Earth masses to Jupiter masses is moved up or down so all ice giants use the same unit (I would prefer Earth masses, but Jupiter masses would be fine too).
It would be better if all planets were in Earth masses, even large ones. It would make comparing mass simpler than using multiple units. Hopefully when the option to choose from different units is implemented this won't be a problem anymore.