I also have a similar problem. Followed the instructions here: Get help using iCloud Contacts - Apple Support but without success.
My problem is that only a part (200) of my contacts from iCloud sync "down" to my 2 iMacs while none at all are synced to my MBA. However, the changes I make on the contacts on either of the iMacs are synced to iCloud and further on to my iOS devices. Contacts between iCloud and my both two iOS devices, however, are identical and seem to sync fine. Notes and other iCloud items also seem to sync fine on all of the devices including all Macs.
Sync contacts is selected on both iMacs. All 3 Macs are running OS X 10.10.1. and iOS devices 8.1.2. My iCloud was sending me messages about space quota being full but I removed tuff a few days ago and currently I have almost 2GB free space.
Tried also deleting my iCloud account on MBA, rebooting and setting it on again. No success.
Any suggestions?
/samuli