Switched from Dropbox to Google Drive a few months ago. the UIs are very similar, and Drive is much cheaper. My only complaint has been syncing:

1) After a week of repeated attempts, I gave up trying to get video from Dropbox to Drive. Maybe the files were too large?

2) Also, syncs are faster and more seamless across devices with Dropbox. There are noticeable lags for most syncs with Drive, even small, single files.

3) Event when Drive thinks it has synced, it hasn't and I have to restart the app.

There are other benefits to Drive, but I never had any sync issues with Dropbox.