Solar is only efficient if you use it all the time, and usually only if you grid tie. Otherwise most solar panels will cost more energy to manufacture than they will give back to you in such intermittent use. (RVs also tend to park in shade, and won't point the awning south as would be required.)

Solar makes sense if you are going to be away from other power sources and fuel for a long time.

If the hybrid RV's power plant is efficient, it would do better from a cost standpoint, though the solar might (just might) be a bit greener.

Even perfect solar (mounted south, grid-tied, sunny location) is not cheaper than grid electricity, even with the $4/watt rebates in California. Of course, this will improve with better solar tech.