Starting around 6.x, -CURRENT got ridiculously reliable (the infamously problematic 5.x release series informed the releng process a lot).

By late 00s, if you were running FreeBSD and pushing it to its limits in terms of performance or features, you'd probably be running current and have at least one committer or active contributor on the team, upstreaming as many business-specific improvements as possible while keeping track of incoming commit stream.