I'm not familiar with Kobalt tools, or Lowes as a tool retailer. After looking it up on the www and seeing the price, you might consider looking at the Sears 10" sliding miter box. Sears has a pretty good record with "low and some mid level" wood working tools.
Sears has been around homeowner grade construction tools for a long time in general they are OK for the majority of the tools used in our hobbies/trade. As for the local Sears, and my personal experience, in the rare moment when there was an issue with something bought (domestic product) they've dealt with it promptly.
Be aware, the power tool sales personnel at Sears, Lowes or any other big box store more than likely never touched any of the products outside stacking the boxes they come in. You might try a local tool sales and repair shop for a critique on either tool, (break downs etc)
Never bite the hand that looks dirty!
The more you know the more you're worth