congrats on the Galaxy S4! 5" screen makes all the difference, plus the fastest smartphone processor on the market, AND you can stick an microSD car in it and kick up the storage a lot!
Honestly, I've only used an excel spreadsheet because if I wanted to add extra notes or put a personal note to me like how I fixed something faster or a tweak I made and need to know about later, I'll have all that available.
When I started spreadsheet, there was no smartphones! And putting notes in a Palm Pilot wasn't very efficient!