Hecrob, this is something we've discussed before - and that I've discussed in the recent issue of CARD CULTURE as part of the article "Card Creation 101," where I talk about an experienced designer, Sarah Ferone, and show how she created and promoted her first deck design, "Cocktail Hour," using Kickstarter.
Kickstarter has more eyeballs, period. There's more chances for "serendipity," a person trolling around looking for cool stuff to back stumbling on your project and dropping ducats on it.
IndieGoGo has a few drawbacks. One is Flexible Funding - people don't like the idea of backing a project, watching them miss the goal and still paying them.
They also support more "charitable" projects, making them appear a little less reputable - some of the "charities" are a bit dubious, the digital equivalent of a faux-bum kid on a street corner in a trendy-hip neighborhood with a begging sign reading "NEED MONEY FOR BEER."
For me, the worst drawback is that IGG makes some of its money on float - when you back an IGG project, they IMMEDIATELY take the money from your account or charge your credit card, rather than waiting for success or failure. They park that money in a bank account and make interest on it (while if you charged it, you're PAYING interest on it) and only refund you if it's not Flexible Funding and doesn't succeed. A project creator can "cancel" the project prematurely and you still won't see your money until the project's end date arrives. Compared to KS, it just feels more sketchy.