Ask HN: Alternative to Bittorent Sync?

I tried to use bittorent sync to share a folder containing hundreds of thousands of files < 100KB each. This didn't work well, as it's taking more than 15 hours to synchronize. Size is 15GB only. A 2GB tar.gz file in bittorent sync takes 10 Minutes to sync. (I have a 100Mbps connection up/down)

So, I'm looking at an alternative, that is :

0) Free 1) Auto update clients's folders when master is updated 2) write and read/only features : I create a folder (I have the write key), and people sync to it but read only 3) ability to handle small files 4) easy to use for windows users without a big knowledge 5) ability to distribute terabytes of data 6) Should work on windows

It seems Aerofs is out of the loop since it's a paid solution. Please don't tell me about rsync, it's out of scope (point 4), etc..

I can see into other P2P stuff like these swarm softwares, etc, if they offer read only that it !

Thanks !