Here in MN, the clinical pharmacists I have talked to have all pretty much said the same thing- "No, you don't need a residency. But the last X clinical pharmacists we hired all had them."
I asked my preceptor at Express Scripts, and: "You don't need one, but having one puts you in a higher salary range here." ESI's clinical services asst director: "I wouldn't have gotten this job right after residency if I hadn't completed one."
I've seen a few writings that state that the year of residency equals three years of job experience.
I'm trying to get into one because I simply want to learn more and become more polished as a clinician. Luckily, the low salary isn't an issue, and its only one year. Will it give me an advantage? Depends on the job I'm applying for, and who the other applicants are.