If you’re going for sharing projects then I use a tool called Resilio Sync (free), although I have used Google Drive successfully as well but only with Logic. Backup’s a bit different, but here’s some discussion…
Firstly, Google, for me it has worked well. I installed their Backup and Sync tool to synchronise a folder on my hard drive with my online Google Drive. In this way I’ve shared Logic projects a few times so I know that it works for me and the other person. Perhaps Logic doesn’t cause so many problems as Cubase?
Anyway, secondly, I use Resilio Sync for sharing Cubase projects, and I’ve been successfully using this with 2 other collaborators with about 30 projects for probably 5 years now (about 35GB disk space, which is why we don’t use Google). This Sync tool doesn’t store the files in the cloud but shares directly between PCs across the internet.
If you’re just after backup then the Resilio might not be exactly what you want, but having said that if you have a spare PC not being used then you can share the data to the other PC and then you have a backup. In fact, I have two non-music PCs which share the Resilio data and one is off-site so I always have a copy of my stuff off site. (Actually, in terms of backup, I also have a backup which runs every night and stores everything on a large 8TB hard disk).
If you’re after remote access at any time then it’s not too difficult to install it and then add the shared folder and the it’ll all download given time… And if you’re after browsing online then you’d have to use the Android/iOS app.