A lot of people here have commented about their mistrust in Google and won't use this service. I thought I'd add my two cents base on actual experience with using Google One.
I signed up the day Google One became available since I had been looking for a cloud storage solution. I downloaded their uploader client and began backing up my files. I am sure the fact that it took over two weeks was a mix of my own ISP upload speed and maybe some limitation on how much the client could handle in terms of uploading files (I had just over half a TB to back up).
That said, the speed wasn't what bothered me. What bothered me was the stupid client kept throwing me errors constantly telling me it couldn't upload certain files (always random) and although it gave me an option to retry, I could click retry a dozen times and it wouldn't matter, it'd simply fail over and over again. My only option at this point was to skip uploading this file. If this had been a few files, that wouldn't be an issue except this was easily hundreds of files with no easy way to keep track of what successfully uploaded and what didn't.
Worse, each time it failed, it interrupted whatever I was doing to pop up a notification with the expectation of me having to select retry or skip. This was insanely annoying. I could be doing something and a notification would pop up and unless I respond, it would just sit there. Sometimes I'd be doing something and the notification would interrupt what I am doing midflow. Needless to say this was an abysmal experience.
I then tried contacting support wanting a refund and to simply cancel. First I tried chat which connected relatively fast but it was obvious the person I talked to didn't know what they were talking about. I then did phone support. To their credit they called me back within an hour though it hung up on me shortly after picking up so I then had to get them to call again and there goes another hour.
Eventually, I did get to talk to a human being but felt I was talking to someone who had very little knowledge about how anything worked. I had to get the case escalated to get the service cancelled since the department that handled that had no direct support.
After waiting about a week, I contacted support again and went through the whole motion all the while finding out it seems like the case wasn't properly escalated. Waited several more days and had to contact support again. It had to be escalated again.
During this whole ordeal, I had already stopped the client, uninstalled it, and removed any files I had uploaded.
After about another week, one day suddenly I accessed my Gmail to find a glaring message at the top that read something to the effect of me being over my storage limit and will soon be unable to receive any emails. I was pissed.
At this point they didn't contact me at all, I haven't seen any refund come through, but my access to Google One was gone so I assumed I was cancelled. But if I deleted all the files I previously uploaded, how could I be over the limit?
The only conclusion I could come up with was any photos I took on my Pixel (which came with unlimited photo storage) somehow was being read as non-Pixel photos so my photo storage blew up. I had to forcibly set it to convert all the images to the format that Google would allow that wouldn't be used against my storage space and eventually after like 2-3 hours my Gmail no longer had that glaring message that I may not receive messages due to being over my storage limit.
Now I'm painfully aware I probably could have backed up all my photos and delete them off Google Photos at this point but I was so exhausted and angry that I just took the path of least resistance here. Eventually the refund came through several days later but this was when I genuinely started to hate Google for the first time.
Hope this helps anyone on the fence about paying for Google One, especially with the expectation that you'll get support as if that'll be helpful.
I ended up going with a different cloud storage. World of difference. Never going to trust Google for anything like this ever again.