Remember, you are not graded on your briefs, the only reason for them is to help you understand the case and quickly be able to get whatever info you need in class.
Personally, I find typing them out easier because:
1) I can use my own words, and shorten things. I tried book briefing and found that I had whole paragraphs highlighted that I could shorten to 2 sentences.
2) I can rearrange things as I like. Makes it a little easier to follow in class to have things in chronological order, and order the different sections how we go over them in class.
3) Can't really unhighlight things you change your mind on including.