Game feels pretty generous so far, despite me not knowing what I'm doing half the time.

Can anyone tell me how much a fully evolved (all stars filled) UC/C/R unit compares to a no evolved SR/SSR/UR? Seems that I can still learn all the skills despite no evolves but is the lack of stats from no evolving gonna be a game changer?? Or do SR/SSR/UR's with no evolves outweigh even a maxed R?