Weighted Vests???

I am looking into buying a weighted vest for my walks/runs. I have no idea what would be a good one to buy. The prices are all over the board. Has anyone out here used one, has one, could shed a little light on the subject and give some feed back? I would love to get a few opinions of real users before I make the mistake and buy the one everyone hates!! *which I have totally done before!!!
Thanks in advance!