I've put my answer a bit higher in the thread: because the competition and customer experience are currently so much worse. (Lyft hasn't arrived in my city yet.) Some of the competitors here have used shady tactics against Uber as well, I've had taxi drivers pull up pretending to be my Uber driver.

If a competitor can match or exceed Uber's service, I'd consider switching. The convenience of travelling interstate / overseas & using the same service I use at home is quite compelling though.