I do like to have a written to-do list and due to the number of voice mails I receive I found it best if I keep track of them to make sure I return calls. I hated my system of keeping track of my daily to-do list, voice mails, etc. because everything was in separate books. I had used the uncalendar planner in several years ago. I was hesitant to go back to it because I wanted to try something new. I searched all over the internet and in stores, but I didn't find what I wanted. I even tried to create my own calendar pages to have them bound at staples, but to no avail. So I went back to the uncalendar.
The pens used on this vary. On Monday and Tuesday I have a purple slicci and a blue/black one, Tuesday the words PTO4 are written with a fountain pen, it didn't do well on the yellow color. (In my experience fountain pens do bleed a bit on this paper but are typically too wide of a point to make them usable for this planner.) Friday, that is a Hi-Tec-C multipen. The maroon color that appears all over is a .4 Zebra Sarasa Red/Black, which is currently one of my favorite pens.
There is some bleed through from the following week on the lower right. That is from a preppy sign pen and a liquid Sharpie highlighter. I don't notice a ton of regular ink bleeding through, problems only occur with markers, highlighters or elaborate doodling.
Overall, I really like this system for the flexibility it has. I can use it differently every week if I wanted to, and I know my usage of the system will evolve over time. If I could change anything, it would be higher quality paper and less use of primary colors. It will be nice if there were other color schemes to choose from.