Personally, the only bad interview experiences I've had were not at startups, but at the big name co's. There's maybe one exception to this, a startup (extremely well funded by bay area standards) that was arrogant enough to expect me to show up without confirming my availability. They hired someone else who did show up on that day and didn't bother to tell me about it. I wouldn't want to work in such a company anyway.

Mostly though, startups have made it a really amazing experience. They have made a real effort to fit the misfits and I owe my career to them.