Pro Trustworthy to store data in the long term
With many utility tools being constantly shut down by their creators, it's really important to consider the long-term risks of picking a home for all your notes. Evernote is a $1 billion company with a track record of exceptional security and goals of becoming a "100 year old" company.
Pro Powerful features for organising your notes
Evernote is designed to make it easy to keep your notes well organized, which aids in quickly finding/browsing old information. You can put notes into a single notebook and use search to access old notes, or if you're so inclined, organize notes extensively with hierarchical notebooks and tags.
Con Security issues
Evernote had their entire database hacked and compromised including customer user passwords. They responded by locking valid users out of accounts and forcing password changes but are still vague about their own security policies. They do not have a good track record for data security. They also do not offer local personal encryption of entire Notebooks as Microsoft OneNote does.