From what I've seen, kickstarter seems to have a higher burden of establishing confidence in the ability to eventually deliver, but with each service it all comes down to caveat emptor and making sure it's something you're willing to take a risk on and a person or group who you have confidence in. Even when I made a substantial pledge for the infamous Coleco Chameleon project on indiegogo, I got all my money refunded. Unfortunately there are swindlers who get through the cracks every now and then, or those who just disappear partway through for whatever reason. You've just gotta be extra cautious about dealing with new people. Sites like those mentioned and even amibay can provide a safety net to reduce the incidence of fraud, but they can only do so much. One thing that I do even when I'm not apprehensive is to try to proceed slowly with purchases from new people, enough so I more or less remember my finances (and outstanding pre-orders, deliveries, etc.) off the top of my head.
