Personally, I fall into both with my preference varying according to the use of my planner.
Whilst some may see decorating pages as frivolous, maybe even a waste of money, I find it therapeutic and enjoyable. Being a busy gal, I seldom have time for as many creative outlets as I should wish to enjoy. Decorating my pages allows for that creative need to be fulfilled.
Furthermore it allows me to map out my week, I know what I'm doing and when. I'm highly disorganised so planning in advance is essential and if I didn't make that an enjoyable task, put simply I wouldn't do it and as such would be back to a semi permanent state of worry and panic about where I should be and what I should be doing.
My domino on the other hand I use for work and I do not decorate these pages. This is for a number of reasons. Firstly, it would not be appropriate for me to attend meetings with butterflies or cats adorning my pages.
Furthermore, I use a day to a page and I use that space. There is not room for me to decorate my pages. Sadly, it just wouldn't work. I still use personalised dividers and dash, but everything else is just kept straightforward.
How about you, where do you sit on the great decorating debate?