The Amazon Echo
http://www.amazon.com/oc/echo/much like siri, it is designed to tell you the new, weather, information and more plus its connected to the internet so it always updates. it is the cheapest compared to the other two.
the personal robot (kickstarter)
https://www.kickstarter.com/projects/403524037/personal-robot
has the most features compared to the other to the other two like home security but it is the most expensive.

Jibo
http://www.jibo.com/
it has less features then the personal robot but is cheaper and has more features then the amazon echo
