I love DayOne for both the iOS and MacOS. Not cheap, but I love that it adds other information such as location & weather. Perhaps useless info to some, but it might be neat looking back at it in the future.
Plus, I love the additions of photographs.
I don't think I have the latest version however. I need to look at that - been way too busy with other stuff.
That said, I absolutely love the sync feature. Pages would have this, but I love being about to type about anything wherever I am and have it synced together.
So for me, it was worth it. Pages might do the trick for you as well.
But honestly, in that case, I would end up using iBooks Author.
The only caveat would be whether or not iBA locks down the file type and what the export options are for different book formats. I've only produced 1 for a family trip itinerary - not for consumption outside our house.
Bottom line: enjoy the process with whichever software you choose. I enjoy journaling. By far not an expert, but I'll have something for my kids to read some day.
Cheers
Brian