I had an incredibly bad experience with this recently. They failed to do the end-of-contract review on time, extended the contract period numerous times after, and when they finally got around to the review said, "we're not a good fit." I actually liked the people and the job, but got the distinct impression it was just a team full of devs that wanted a devops to clean up their terrible infrastructure mess, future proof it, and then let them go.

Never again will I do contract-to-maybe-hire.