I used to sync my outlook exchange account, but then my organization implemented a screen lock requirement so I stopped syncing using the stock mail app and went to the Outlook Web App instead. This gives me the freedom to choose whether or not to use a screen lock and I only need to enter a 4 digit code when I decide to check my email.
I use AkrutoSync to sync Outlook calendar and contacts with my Android. I have other non-Android devices (I'll be nice and not mention them here) and sync with those too. There's no limit on the devices as a license covers one PC. You can try the full software free for a limited time to see if it's for you.
I've used Akruto with Outlook 2013 and 2010. You can sync Outlook calendar with Galaxy S5. I've also upgraded Android phones, installed custom ROMs, and Outlook sync still works. But it's not free. However, you can try it free to see if it works for you.