I've been using Evernote for almost 4 years now. Overall, I like it. Having access to the same information on my desktop, laptop, tablet and phone is amazingly handy, especially at events where I go through multiple sets of batteries in a day. (SXSW comes to mind.)
The key to using Evernote, or probably any personal content management system, is organizing your data so you can find it later. I started using notebooks, but have evolved to a combination of notebooks and tags. It's important to spend some time up front, and create some management system and stick to it. It will evolve, but as with many things, if you have a good base, it will grow well. I use the notebooks to separate major contexts; like work and my various hobbies. I use the tags to keep track of individual subjects. This is handy when a given item can fall into more than one category.
I like that you can use the camera to embed pictures into notes. You can also embed other files. The free version has a fairly modest limit on the amount of data you can upload, but it's been adequate for me. You can upgrade to the pro version for $45/yr, which gives you a lot more upload and I think some enhanced OCR capabilities as well.
I also like the web clipper plug-in. It will extract the content and put it into a note. This is very useful if the content changes or even disappears. They've been steadily adding features. I'm getting into the shortcuts and reminders and finding both useful.
Going back to your original application though; if you want to keep a journal, keep a journal. Adding organized, indexed notes to it will be amazingly useful. I do keep an irregular journal on Evernote. Though, if I have an ongoing need for detailed tracking, I switch to pen and paper, usually in the form of a Daytimer. I do this for legal reasons, and not operational ones.
My only major criticism is that the iOS app is very slow on my iPhone 4.
Please don't construe the above as a diss on One Note. I haven't used it, and haven't been motivated to try it.