Descent:Underground [0] and Starfighter Inc. [1] both had well-seasoned teams of industry veterans, including founders who had written popular space games (X-Wing, Wing Commander).
One of the big differences I identified between the two campaigns was that D:U asked for an amount of money that seemed like enough to run a small game studio for a year ($600,000) while SI asked for an amount of money that seemed like it wouldn't get them anywhere close to done ($250,000 for a bigger team). D:U was also really clear in their messaging -- if we don't raise the funds, that's a market signal that we shouldn't make this game. SI communicated several times that if they didn't reach their KS goal they'd just do it another way. What that indicated to me is that D:U had a realistic crowdfunding plan that could get them to release, while SI seemed not to know what they were trying to accomplish with kickstarter.
To be sure, there were a lot of other factors at play. With D:U, Eric Peterson pulled a lot of support from Star Citizen backers and they released an excellent trailer in the last 48 hours of the kickstarter. SI dodged questions about what engine they were using and had a number of other customer interaction problems. But I think one of the big issues was that they didn't ask for a realistic amount of money, which made it seem like they either didn't know what they were doing or were relying on additional funding which would increase the risk for kickstarter backers.
[0] https://www.kickstarter.com/projects/descendentstudios/desce...
[1] https://www.kickstarter.com/projects/impellerstudios/starfig...
$50,000 could have afforded them an artist for 6 months, or helped them to secure some essential software, or just supplemented the incomes of the existing team, while they continued doing 'side-jobs' to generally pay the bills.
Now ideally, they would get all their funding from one source (so we know what they received) and it would be enough to pay for everything. But I think a lot of people who pledge on Kickstarter have a gross misunderstanding of how much money a game takes, considering each team-member may have a salary ranging from $50k - $100k is not unreasonable at all.
I see a lot of kickstarter project where a team of 5 is looking for 20K or somesuch. While some teams can and do pull it off, that just seems crazy low and too much risk (especially when you factor in KS' fee and cost of rewards).
EDIT: Removed the as a rule from the first sentence (was I, as a rule, won't back...). After reading andallas' reply, I realised that there are some very rare occasions where I do back projects I otherwise wouldn't, but they have to have really proven themselves.