I was also wondering how useful Echo would be since I rarely use Google Now. As an Echo user, I can tell you it's vastly different. Echo is always there... always ready and it's surprisingly very fast. The array of microphones works great and Echo hears me from very far away (in other rooms out of line of sight, down hallways, etc). Google's voice recognition is probably still better and I do have to repeat commands sometimes - but I can be anywhere in the apartment and Echo works well.

When I'm getting ready in the morning, I will rarely check the weather on my phone because first, I need to find my phone (I seem to put it in a different place every morning) and then I need to click multiple times to see the information I want. With Echo, I can say "Alexa, will it rain today?" or "Alexa, what's the temperature?" and get an answer instantly while I'm doing other tasks. It might be less useful for smart watch users that wear them 24/7 (I don't own one).