I've been in this business for long time, as a customer and as a company rep. Just until recently, I worked for one of the biggest cloud storage/computing supplier. Proper cloud service of any kind is expensive. Free service or something given to you as part of hardware purchases aren't. But they do cut corners everywhere they can, and hide them in fine prints, which you ok'd without reading.
Personally, not that I have any top-secret content, but I don't trust cheap suppliers ability, budget, or willingness to keep and keep secure my files for free. I just don't trust them. My files are valuable to me. If I have to keep it elsewhere, I will pay premium for it. Since it's not a possibility, I do it in-house. (literally....)
Also, I found using old desktop or servers can be a false economy. Today's machines are quite efficient in terms of power consumption. It's far cheaper to run 2 disks mirrored than 10 disks in raid 6.
I also try not get attached to company's proprietary anything. I considered it but abandoned those NAS box ideas early on. Can I recover data if CPU board dies? What kind of filesystem are they? Can "secure protection" be bypassed by me, the owner of the file, to read content on another machine? All those were considerations.
In the end, I ended up with a new generic Linux server, spare parts, and software raid. Having worked in hardware/software support for total of 20 some years, I don't want to depend on them to get my precious files back. I am my own support.