The ownCloud sync client for OS X pins one cpu core to 100% usage on my fairly new i7 mbp, which effectively drains the battery quite quickly if you don't notice.

Then it also seems to do a full scan of teh entire folder each time it sync's, if you then have for example your iPhoto library (usually a few GBs) there, the sync process will consume lots of CPU and tend to be out of date across devices.

I heard ownsync is really buggy. Havent tried it though.

Wuala used to be P2P (host other people's files to get more space for your files) until LaCie bought it.

+1.

I'd like to know more about this. Working on a encrypted FOSS alternative to conventional storage would totally be a perfect side project