I have been using MPE for a long time, manly to sync my Androids with Outlook. As a by-product, I also transfer contacts, calendar etc. to new phones.
Recently bought a Xiaomi Note 3, and it turns out that contacts do not sync: apparently the phone's contacts storage location is not recognized by MPE, so MPE reports that the phone does not have any contacts, and asks permission to download. It then downloads, but these downloaded contact items are not recognized by the phone . . so nothing happens.
I finally transferred the contacts through a backup application (Super Backup Pro) and the SD card. It works, but is also a pain in the you-know-what.
Wish MPE would handle Xiaomi . . they seem like pretty good deal, and are getting an increasing market share.