In Ireland the app went from being Hailo to MyTaxi to Free Now. Personally I loved Hailo. It became a verb and it was common to say "I'm going to Hailo now". Now it's "I'm going to FreeNow... now". It just doesn't sound as smooth. I still use it but I really feel like Hailo was the ideal name.
Hailo sounds like an extremely clever name for a taxi app, since (at least in US English) one might "hail" a traditional taxi. FreeNow seems clunkier to use as a verb, plus it doesn't seem to connect to the service at all. (Unless the taxi ride is free now!)
Yeah, it worked well. I guess the problem you have is, once you're international, your clever name loses its impact. It was a common joke at the time Free Now launched that the taxis should be free alright.