It's true that Spirit were a very album-oriented band, one that might best be experienced through albums rather than compilations.
If a compilation's good enough for you, this is a good one to get.
Granted, the band's mere handful of well-known songs are gotten out of the way right away ("1984," "Mechanical World," "Nature's Way," "Animal Zoo," "Fresh-Garbage," "I Got a Line on You").
But the rest of it's pretty solid too, including "Uncle Jack," a high point of pseudo-Beatleish psychedelia.
Given the tendency of some of the albums from which these are taken to meander, this is actually a good alternative for the listener who likes Spirit's most accessible tunes, but isn't enamored of their full-length works.