I've been suffering from the same problem. I use Outlook for business and depend on having my Outlook calendar (and other info, but especially calendar) readily available on my phone.
The solution I came across is Akruto Sync, which I am currently evaluating. So far looks great.
All the details of my Outlook data appear to be included in the sync.
After the initial install, it is fully automatic. Once I get within the range of my wireless network, the phone connects to my computer automatically, syncs and stays synced.
Akruto Sync uses the native apps on my S4, so I don't have to switch to some other app. I can continue to use the standard calendar, my old widgets, etc...
I will evaluate it some more, but I think I've found my solution
