Smaller is faster and better.

Little o

f(n) ∈ o(g(n))

f < g

Big O

f(n) ∈ O(g(n))

f ≤ g

Big Theta

f(n) ∈ Θ(g(n))

f = g

Big Omega

f(n) ∈ Ω(g(n))

f ≥ g