If I was looking for a f/t job I might use LinkedIn, mainly because so many recruiters use it. In my own career, both with f/t jobs and freelancing, referrals and word-of-mouth always work best. A good recruiter can put you in front of hiring managers, but I would prefer finding a good recruiter face-to-face rather than on LinkedIn.

I think the worst way to find a job is filling out applications online and blindly sending in hundreds of resumes. LinkedIn at least sits a notch or two above that.