The appeal of the files on my MacBook Pro being available on all my computing devices is huge. I started using an iPad Pro recently, and that experience made me decide to drop $100 a year or so to test how well I could work on files across devices. I already have DropBox and Google Drive accounts. I have lots of Google documents made using Google's office tools. Those files are not available to DropBox.
I started with DropBox. After buying 1TB, I dragged my "documents" folder into the DropBox folder. The upload then proceeded and took three days to move about 142GB of files. After that was over, It seemed that any new file being moved to the DropBox cloud seemed to take a long time. I did a Web serach and found others moaning about the pace set for DropBox files to move.
Editing files using DropBox on the iPad was easy enough. But DropBox syncing seemed to slow down performance. Plus I missed all the document creation tools in Google. So I have now started using Google Drive after purchasing 1TB of space. I installed the Google Drive app for Macintosh.
The "Documents" upload time is taking a third as long as DropBox. Already a good sign. All my Google made documents are now in the same place as all my laptop documents. I can now organize the combined files by category rather than having two directory structures. This is huge.
Viewing photos in Google Drive is quick. I use Lightroom on the laptop, and because Lightroom uses the OS's file structure for it's photos, I can review photos that are in Lightroom on mobile devices by navigating the directories I set up in Lightroom.
I'll update my experience as I merge my Google made documents with my local files.