Would you rather build something new or jump into an established company/org?

I recently started a job at a start up where I am building an outbound sales team from scratch and have discovered something about myself- I don't like to build things... I'd rather manage a team (at a small or large company) that is already somewhat established.

For those of you who have done both, which do you prefer?

For those who have only done one or the other or neither, which do you think you'd like best?

Side note: I'd argue both options are important experience.