See:

Google rolling out Drive for desktop
Google’s new Drive app replaces Backup and Sync with Drive File Stream | Ars Technica

I'm using 'Backup and Sync', which is the current iteration of the Desktop Client. This works perfectly fine for me as it is. I have a Folder on my secondary drive and anything inside automatically syncs. It's unintrusive and seamless. It appears the writing is on the wall for that client so i tried out the new thing.

Firstly i was somewhat confused that the existing Backup and Sync client was not replaced. The new client installed itself as a seperate program. There was a new icon in the System Tray, alongside the old one, and a new entry in the Start Menu. There was a new 'Drive' in This PC which was automatically populated with the Folders that i was already Syncing. This Drive was automatically assigned the Drive Letter 'G:'. (The new 'Drive' was also automatically added to 'Quick access'). Right clicking anything within this Drive showed a Context Menu with a slew of new Google Drive options.

The new Settings page could be accessed from the System Tray icon, but most of the ones mentioned in the Ars article were missing. I assume that if no other iteration of the client is already present, the new one would have all the options. With the old client installed it appears that the two are designed to live side-by-side with the settings spread out between them. It's very odd!

I am not a fan of this change. The new 'Drive' is nothing more than a 'Library' where all your synced folders appear in one place, no matter the actual physical location. I'm never going to need this 'Drive'. Any change i make to files will be in the actual Folders that i already have Synced. I don't need a pretend Drive just sitting there in Windows Explorer annoying me. Mostly i'm not a fan of having both Clients running side-by-side. I didn't know what would happen if i tried to uninstall the old client with the new one already in place, so instead i removed the new one. Perhaps it's better to remove the old client before installing the new one?

I've always enjoyed the convenience of automatically syncing to the cloud, but once the old client is deprecated i'll probably uninstall it and sync manually using a Browser instead. Anybody else tried this out yet?

Edit: Someone else not happy with the current changes with examples of why it might cause problems: Google Drive for Desktop: What was Google thinking? - Google Drive Community