When I first heard the news that there was a Drupal fork, I was pretty surprised and doubtful. Then I heard who started the fork (Nate Haug and Jen Lampton, really respected Drupalers), and I got a lot more interested, really fast. I've been playing with Backdrop now for a couple of weeks, and have even contributed some pull requests. It's helped me understand better the rationale behind the fork, and helped me think about what might happen moving forward.
As developers, saying "no" to clients sounds, on it's face, like a bad idea. You want to do what the clients need, you don't want to upset them, and, frankly, you want the hours. But the truth is, in order to build websites that are cost-effective and sustainable, you have to say "no" sometimes.