Raising convertible debt from venture capitalists can restrict your Series A options and lower your Series A valuation—whether or not your investors have a right of first refusal on the Series A. You can keep your options open by raising debt from angels exclusively or raising debt from more than one VC.
(Full Post: http://venturehacks.com/articles/options-open)
Babak Nivi is a co-founder of AngelList and Venture Hacks. Previously, he was an entrepreneur-in-residence at Bessemer Venture Partners and Atlas Venture. He has worked on startups including Songbird, Grockit, and Kovio. He went to school at MIT where received 2 patents and published in Science.