Same here, the OS works fine.
You don't have to upgrade but since it's free I see no reason not too.
There will be a time, a bit away I expect when some apps will require Mavericks but as I say that may be a while.
My only criticism of Mavericks is that Apple make it (more or less) compulsory to use iCloud if you want stuff - primarily calendar & contacts - synced with your iPhone/iPad etc.
Now when it works it's fine but when it goes adrift it does so big time as I discovered when I got a desktop calendar with everything duped and an iPhone with zero entries. Fortunately I'd got loads of backups just in case.
Lots of swearing and emails but eventually I did get it sorted. However I'm very wary of the whole system and don't really trust it.
Synology NAS do come with calDAV so you could sync calendars at home using one, although AFAIK neither they nor QNAP supply anything like cardDAV that will sync contacts.
xela (fountain of knowledge)
Sun 27-Apr-14 16:52:58