I use Evernote. But I don’t trust it.
I use Evernote for most of my digital notes stuff. I like the syncing feature which keeps notes on my mac, smartphone and tablet in sync.
However I don’t trust it for really important long-term stuff. Really essential stuff, such as long writing projects, articles, essays, important letters or digital journals go into textfiles that are in directories covered by redundant backup/archive mechanisms on detached portable HDDs with filesystems that can be read with widely available free open source software (Mac OS X HFS *without* journaling).
Doing anything else with anything valuable that’s supposed to stay useable longer than a decade is insane.
For instance, I still have CD copies of CD Archives of Zip Disk Archives of very old HDDs (2,5 40 MB HDDs would fit on one ZipDisk attached via parallel port - yepp, those were the days) with texts written in Ami Pro. The Ami Pro format is openable with a regular text editor, but it still is anoying to extract the useful data. No way am I installing Dos 5 and Win 3.11 on a Vbox just to run Ami Pro just to open them. Hence, only UTF-8 textfiles since round-about 2000.
You should do the same for any journal stuff that is supposed to last longer than 3 years.
My 2 cents.