Just personal preference!
Back when I used pen & paper (I now track using eTools), I liked the 3 month journal, because it was small enough that I could fit it into my purse, but I could look back if I needed to remember the Points of something. The layout was nice, and it was a firm reminder of all my hard work.
However my mother likes the smaller weekly tracker.
There's nothing wrong with either method. It's about whatever keeps you tracking