For me, KS was a pretty straight forward choice as far as exposure and access to the market went. I did consider Indigogo but noticed projects floundering there. I doubt there is anywhere else with the same potential traffic for a first up campaign, so for that I'm thankful it exists. And right now KS is obviously a powerhouse for card campaigns.
That said, the pledging system is so crude it amazes me. To be unable to choose add ons when you pledge seems bizarre. To have to manually add up the cost yourself. And for myself being unable to work in US dollars. It meant I had no idea of production quantities until well after the campaign was complete, pledgers who couldn't remember what they'd pledged for, incorrect shipping amounts etc. Services like Backerkit have jumped in to fill the gap but it really should be part of the KS system to start.
KS and the payment system do carve about 10% off your total also, but again it's hard to beat the exposure.