I knew about e-readers before Kindle, but didn't buy one till I saw the right combo of good user interface and access to books. It also made a big difference that I trusted Amazon to stick around longer term, and to offer good customer support. Marketing didn't work for me; I prefer to research and compare.
I've also ended up buying a handful of Kindles as gifts. When I buy, though, I consider what would best fit the recipient. For some people I've bought for, a Nook or an iPad was a better fit. Just because I like something doesn't mean it's ideal for someone else.