For those of you still struggling, here is a literal translation.
"Compared to the best [we are] not sufficient. Compared to the worst, there is remainder."
比 bi3 is our core verb here, "to compare"
上 shang4 here means "the best"
下 xia4 here means "the worst"
不足 bu4zu2 means "insufficient" / "not satisfactory" / "not enough"
余 yu2 means "extra" / "remainder" / "surplus"
A good translation is:
"Compared to the best we aren't much; [but] compared to the worst we still have something more."