I haven't played Beyond All Reason but looking at the system requirements I'm not surprised it is more fulfilling. 0 A.D. runs on a potato if you look at it threateningly, which makes it a good option to have on a throwaway machine for kids or somesuch.
My experience is the opposite: 0ad will lag on my laptop once thing become big. BAR will warn that it’s not compatible with my low end intel integrated potato gpu, but it works just fine..