Personally I prefer OneNote over Evernote, but mainly its because I handle most of my stuff on a PC. OneNote's PC program is waaay better than Evernote on a PC. However, if you handle stuff more on a tablet/phone, Evernote is a better choice since the app is waaay better than OneNote's app.
I've been with Evernote for well over 10 years, more like 20, or ever since they showed up on the market.
I have never tried OneNote so can't argue the merits of it at all.
I do use Evernote's cellphone App every day, in fact many times a day.... and I have to be very careful to keep records accurate and Evernote has not once fouled things up.
I have though,
learned that you do NOT want to have Evernote open on two devices at the same time...... you end up with what Evernote calls "Conflicting Pages" and resolving that is a Friggin mess.... I once just tried to delete the "conflicting page" and everything disappeared.... gulp!
that was when I changed my methods of editing.... never, ever, open it on two devices at the same time.
( I am pretty sure this rule will be identical for all Note products that sync up thru the cloud )
for one of my clients, I keep 3 copies of their stuff in Evernote, labeled Customer, Customer1, Customer2.
1 and 2 are backups of the original stuff.... from time to time, I will copy/paste from the original to the backups....
when the S*** stuff hits the fan, you do not want to have to try and explain why you "lost it all".