MS can't "push" hey cortana to the 830, even if they wanted to. I explained why here:
http://forums.windowscentral.com/wi...5-what-exactly-sensorcore-answers-inside.html
Both devices have their own set of drawbacks and advantages. If you play games with a lot of 3D graphics, go for the 930. I don't play games on mobile devices, but I did take a look and found the 830's GPU to be underpowered for such tasks (asphalt 8 is one example). For me, the biggest advantage the 930 has over the 830 is the AMOLED screen. Many will disagree with me, but I personally much prefer the blacks and contrast on AMOLED displays over the 830's LCD. Hey Cortana is nice, but consider how often you'll be using it. For me that might amount to pressing the search key once less often per month... at most. No big deal for me.
On the other hand, the 830 is not slower in everyday use, but it is lighter, thinner, and has better battery life, it never gets really hot, and supports glance. Overall, for me, that makes the 830 the better device. YMMV.