From the YC-run "How to start a startup" Stanford class:
> Then the question is: where do you form one? Theoretically you have fifty choices, but the easiest place is Delaware. I'm sure you're all familiar with that as well. Delaware is in the business of forming corporations. The law there is very clear and very settled. It's the standard. The other thing is that investors are very comfortable with Delaware. They already invest in companies that are Delaware corporations. Most of their investments are probably Delaware corporations. So if you are also a Delaware corporation then everything becomes much simpler. There's less diligence for the investor to do. You don't have to have a conversation about whether or not to reincorporate your Washington into Delaware.
> We had a company at YC about two years ago that was originally formed as an LLC in, I'll say Connecticut. The founders had lawyer friends there who said that this was right way to do it. When they came to YC we said, you need to convert to Delaware. The Lawyers in Connecticut did the conversion paperwork and unfortunately they didn't do it right. They made a very simple mistake, but it was a very crucial mistake. The company was recently raising money, a lot of money, and this mistake was uncovered. The company thought it was a Delaware corporation for a couple of years but in fact it was still a Connecticut LLC. I'll just say this: four different law firms were needed to figure that one out. Two in Delaware and one in Connecticut. One here in Silicon Valley. The bill right now is at five hundred thousand dollars for a conversion mistake.
> Then the question is: where do you form one? Theoretically you have fifty choices, but the easiest place is Delaware. I'm sure you're all familiar with that as well. Delaware is in the business of forming corporations. The law there is very clear and very settled. It's the standard. The other thing is that investors are very comfortable with Delaware. They already invest in companies that are Delaware corporations. Most of their investments are probably Delaware corporations. So if you are also a Delaware corporation then everything becomes much simpler. There's less diligence for the investor to do. You don't have to have a conversation about whether or not to reincorporate your Washington into Delaware.
> We had a company at YC about two years ago that was originally formed as an LLC in, I'll say Connecticut. The founders had lawyer friends there who said that this was right way to do it. When they came to YC we said, you need to convert to Delaware. The Lawyers in Connecticut did the conversion paperwork and unfortunately they didn't do it right. They made a very simple mistake, but it was a very crucial mistake. The company was recently raising money, a lot of money, and this mistake was uncovered. The company thought it was a Delaware corporation for a couple of years but in fact it was still a Connecticut LLC. I'll just say this: four different law firms were needed to figure that one out. Two in Delaware and one in Connecticut. One here in Silicon Valley. The bill right now is at five hundred thousand dollars for a conversion mistake.
http://startupclass.samaltman.com/courses/lec18/ (transcript from http://genius.com/Kirsty-nathoo-lecture-18-mechanics-legal-f...)