Optimizing Exchange Online syncs?

In 8.0.1. it seems to take a rather long time to complete an Exchange Online synchronization. I was wondering if anyone else has any base data on this as fetching a single mail user seems to take 10 - 20 seconds for example and in an environment with tens of thousands of these (+ all other objects) this piles up to a rather long sync even if you set it as a revision sync. 

Anyone having similar experience and has someone witnessed if there has been an improvement to the cloud sync speeds in the later versions (8.1. & 8.1.1) ?