Can DTTG Support iCloud To Sync Files? The MobileSync is not very easy to use. 
No. None of the cloud services are supported for use with DEVONthink To Go.
Thats why I like DTTG so much. I have control over my info, nothing ends up in clouds just a password away.
I use TimeMachine for backups and all info stays with me. Traveling a lot and an added benefit is that you don´t need to spend money on data with Verizon for using DTTG.
Seen so many of my friends having lost data because of clouds and also passwords drifting around. Be safe, keep your data locally.
4th conceivable method now possible for DEVON to utilize for enabling iCloud for syncing possibilities:
developer.apple.com/news/?id=02042016a
I feel the same way. Once it works well, then again not. Currently I regret the purchase.
iCloud is great.