Everyone has their own personal preference. I've been using 3/16" thick beverage tubing for a while now and have gotten fed up with residual flavors and plastic taste in my beer. Did some googling and found out that vinyl (and PVC) leach out plasticizers, bisphenol-A, and some other great things for the human body. So I did more googling and have just upgraded my lines to 1/4" LLDPE (Linear Low Density Polyethylene) tubing (25' to keep my system balanced).
I haven't run beer through it yet so I'm not 100% positive on the results, but if it works, it will be healthier/safer than vinyl. Vinyl will work, I just prefer to go with ULTIMATE food grade/safe as possible.