Mega does have a generous free plan, but from what I have read, they have a strange background which I don’t really want to explain here. You will most likely be able to find the reasons why in this forum, if you do a bit of searching.
Tresorit is a great service, but as a explained in my original post, they have limitations on the the upload size, and that you can’t upload files bigger than 10GB. Other things that I didn’t like are that you can’t files above 2GB and you can only have 3 devices connected at once. Tresorit is still a great service despite those limitations. I would most likely recommend it depending on what the user is looking for in a cloud storage option. For me, it wasn’t an option as I was thinking about the long term of me using Tresorit.