KS is tied to Amazon Payments which is only available to US "persons" and UK "persons" which is legal residents and companies. Available meaning who can receive money, not send it.
IGG is tied to PayPal which works both ways for most everyone in the industrialized world.
They are pretty much the same thing. If you think KS is safer then you are just setting yourself up for getting burned. KS doesn't actively enforce a damn thing so any claims to the contrary, like having working prototypes, is bullshit. I've had KS campaigns I've subscribed to totally change the entire product design after they were funded. Oh jeez, sorry, we decided to redesign the whole product and feature set but the good news is if you want a refund you have till Thursday to claim it. WTF is that? So much for a "prototype". Pure bullshit. The screenshots are just as mocked up on both sites. The only crowdfunded project I've participated in that's even close to what they said was going to happen is on Indiegogo.
Projects which add more and more and more features during the course of the campaign as stretch goals or perks are the least likely to succeed on either site and neither site requires that the specifications be known fully in advance or that they not change. How prototyped is a product which is little more than a rough idea when it's funded for production? The fact is most of these projects need the money to finish the design first, hence the spec waffling after funding.
KS doesn't always enforce their rules, but recently they have been. I've seen projects shut down completely. I've seen projects where the project owner tried to add reward tiers that violated the "no multi-item sets" rule and KS simply deleted those tiers and cancelled all associated pledges (without so much as a warning). And I've seen quite a few projects where the project owners were downright complaining because they weren't allowed to show incomplete portions of their designs (or designs related to "stretch goal" addon features) due to the "no renderings" rule.
KS does not offer any funding model that resembles the "Flex Funding" of IGG - which IMO is essentially a blank check for scammers. It also provides considerably better communication tools between project backers and the project owners. On IGG, you can only post comments with a limit of 500 characters, and you cannot post comments that relate to specific updates - there is one single feed for the whole project. This is awful for accountability on larger projects.
I've backed quite a few on KS now (30+), and while yes many of them are/were late as hell when it comes to delivery, the vast majority have been exactly as advertised.
Yes, when they give in to pressure from backers for "stretch goals" (I f*cking hate that concept, btw) it almost always ends up causing major delivery delays. But the big killer is when a project is too successful. Making 100 units of a product in your own basement is entirely different from mass producing 5000 of them - and that's what devastates the delivery schedule of most of them. Even people experienced in bringing products to market can be swept off their feet when they end up selling far more than they had planned for.
You are making a very thin, paper thin, argument about what differentiates one from the other. They enforce their rules when backers complain. They are inconsistent at best and they are in fact perverting the model by presenting these "products" as things you can "buy" like you would on Amazon. Allow me to explain what I mean.
If you are "buying" things on Indiegogo then you are doing it wrong. Crowd-funding is just that: funding. Getting one or some of the things you are helping to fund the creation of is a "perk", they don't call it that by accident, it's not a purchase. When you give $125 to fund your local PBS affiliate you get a handy tote bag and a DVD of bird songs as a gift, a thank you. You aren't purchasing the merchandise, you are supporting a cause which is commercially insupportable. This IS the model crowd-funding and Indiegogo is based on.
If the project fails to produce the thing they asked for the money to do then that's the way it goes. You need to decide which projects and more specifically which people are worthy of your support. You have to decide if it's something you care about. Is it something you'd like to see happen even if there is no commercial source willing to fund it? Is it something you think the people behind the project have a reasonable chance of being successful at? If you want to "buy" a gadget then wait until they finish making them and start selling them on Amazon ready to order.
If you are crowd-funding something because you don't want to invest you own money or you don't want to borrow the money or you don't want to go find a venture capitalist to fund then you are going it wrong. The whole point, and if you read Indiegogo's mission statement you'll see, is to fund the otherwise un-fundable. That's why crowd-funding exists. Some things just can't attract commercial funding so they ask the general public "the market" or "audience" if they would help make it happen. There is a reason why there are perks which don't include getting the thing that is being funded. There is a reason for the $5 perk which gets you nothing but a thank you. If you didn't know why those things were there before, now you do.
The reasons projects like the one in this thread fail to attract funding is they are trying to sell a product rather than achieve some higher purpose through the creation of the thing. The OP is asking for money to make these things in quantity to make them cheap, he essentially wants a line of credit. The only people who will fund this project are people who are doing it wrong, pre-purchasing a product with an extended delivery date. That's why he's sold $525 worth. If he instead asked for the money to accomplish some ridiculous goal like teaching all the kids in Africa to program FPGAs then he would probably be oversubscribed by 3000%.
When people give you money on Indiegogo they do so because they like what you are trying to do and they want to help you accomplish it. They might want the thing you are making but they many not. Successful projects always get a large percentage of their funding from non-product perks, the $1, $5, $10, $20 and so on. Rule number #1 at Indiegogo is always have a $1 perk. They aren't just making that shit up. In addition to giving you some money, backers more importantly spread the word about your project and how cool they think it is to all their friends and followers. That's why they are successful!! Unless backers share your project on Facebook and twitter it isn't going to be successful. They aren't going to do that unless they think others would be interested in your cool project too, it needs to be tweet-worthy. They become advocates for and reflectors of your message. That gets you more funding.
If you don't get why some crazy projects are way oversubscribed and other perfectly sensible ones have almost zero backers it's because you don't get crowd funding. You will be burned because you don't understand what you are getting into when you hand over your credit card info. The Indiegogo blog explains much of this in detail. I used to think about it like you do until I sat down and had a conversation with one of the founders of Indiegogo at an event and she explained it to me quite eloquently.
If you and your high school science club want to build a satellite and launch it into space to find alien life on distant planets then you do it on Indiegogo because nobody else is crazy enough to fund that shit. No prototype required. Yes, this was a real project I myself contributed $65 toward and as a perk I get a picture of a picture of me in space with the earth in the background. Will I ever get it? I dunno, it would be nice but I gave these kids the money for them to try, not necessarily succeed. Richard Branson gave them $100,000 for largely the same reason.
You poo poo Indiegogo because you don't understand it. Many if not most of the people posting in this sub-forum also don't get it either. If you want to shop for electronics, don't do it on Indiegogo, or Kickstarter, despite their claims of deliverability. If you want to sell electronics, you probably won't get the funding.