I've had the Echo for a few months now, and despite being skeptical of voice control in general, have been pleasantly surprised by Alexa!
Realistically, I haven't found all of the promoted features as useful as they try to make them appear. So far, it has been most useful for:
- setting timers while cooking, so I don't have to fiddle with the crummy interface on my microwave with my hands covered in goo
- turning off lights after I'm in bed
- setting an alarm for the morning
- asking "what's the weather" while I'm getting dressed
- adding things to my grocery list