Like all database files, Quicken files should be closed before backing them up. If Quicken has an "Export" or "Save as..." option, it would be best to use these to save the data in a separate file, then have SpiderOak One or Groups back up the separate file. Otherwise, close the Quicken application before you back up the Quicken file.
Again like all database files, Quicken files should not be synced. They can be backed up if the above precautions are followed, but database files should be synced.
Some versions of Quicken for Mac use the package file format. A package "file" is in fact a folder that the Mac Finder and certain other software shows as if it were a file. Our job however is to faithfully back up and display files and folders without manipulation, so SpiderOak One and Groups will show you what the "file" really is, a folder. When working with such files, or indeed any package file, you should back up and restore the entire folder.