A lot of this was really good but I disagree with three points. You shouldn't stop using ID's unless you have a reason to. Mixing dashes and underscores is just ugly. And finally he calls @import after he declares his own styles which will override anything that he just declared. That is the opposite behavior of what you want it to do most of the time. Beyond that most of it is a good write up and has some really good rules that really help keep your SCSS clean and organized.
>You shouldn't stop using ID's unless you have a reason to.
The opposite approach is more useful: don't start using ID's unless you have a good reason. Classes can do anything (CSS-wise) that id's can, and lack the downsides (namely reusability and dealing with increased specificity, here's a pretty good write up: http://csswizardry.com/2011/09/when-using-ids-can-be-a-pain-...)
