Rationality of the probabilistic zeta function of finitely generated profinite groups

We discuss whether finiteness properties of a profinite group $G$ can be deduced from the probabilistic zeta function $P_G(s)$. In particular we prove that if $P_G(s)$ is rational and all but finitely many nonabelian composition factors of $G$ are groups of Lie type in a fixed characteristic, then $G$ contains only finitely many maximal subgroups.