Seems more and more people are talking about Xero these days. I was surprised it didn't come up in the comments above. I've heard old QB fanatics declare they have been utterly blown away by how much better Xero is.
That said, I haven't tried Xero, so I can't speak to it. And I have dear friends at Intuit who I know are very committed to making QB better, and I'd never bet against them.