is there a better way to do this? want basic dead simple usage.

This seems fine to me, although strstr() will match fa-doughyperson because it contains gh. Although it doesn't matter here, strtstr() also has unnecessarily bad performance if the haystack is large and the needle matches early, because it must copy most of the haystack to return it. This is probably better, since it won't match ghost or fa-doughyperson, will never examine more than 3 characters, and runtime is independent of the size of the string.

if (!strncmp($this->iconFont, 'gh-', 3)) { ... }