No, the quality won't be compromised. I use OneDrive for syncing between my computers and all cloud systems will give you the file back in the same quality you put it in.

Hey Addam,
I started using Onedrive also and its seems like a good solution except:
1) Disappearing cues,grids,loops(rarely) color code stays the same though- songs get reanalyzed it seems
2) If I add music on a different PC to Onedrive, does it need time to copy to laptop before i can add it to my Serato library?

1) You might be overwriting metadata if you don't let the files fully sync before changing them. In those cases, there typically are duplicate files in the folder since OneDrive is pretty good at duping the file if there are conflicts.
2) Yes, the files essentially pull from the cloud, so it'll need time to download/upload files if you've updated on a different machine. You can use the OneDrive icon to determine what it's down or uploading. Also note that if you are using the newest Windows 10 update, you'll need to make sure that the "Files On-Demand" (more info here: support.office.com) is off or you may be seeing the files, but they wouldn't be downloaded.

Thank you. That makes sense. I appreciate your response.

It's only a bad idea if it's your ONLY backup.