I pay for both and pCloud is cheap but inferior (for me) in two ways:
1. pCloud doesn't support file permissions or symlinks, thus you can't use it as a real filesystem (eg, building and testing software out of it).
2. pCould is a "cloud fs" (the files aren't on a host filesystem), whereas Dropbox is syncing a host filesystem. The difference is very visible in performance.
If the first issue was fixed (I've asked them many times, to no avail), I could live with the second.
Number 2 pCloud way is to add sync folders, you do that from the Sync tab in the preferences dialog. Sadly the command line client doesn't let you add the sync folders. An alternative for the GUI is to edit the sqlite configuration file.
In my experience pCloud works fine for me having the Documents, Music and Pictures folders synced, and having many other folders as cloud only.
