I agree that shadow copying is a must. With this enabled, there is no need to enable windows' own shadow copying, which essentially will create redundency. Also, windows' own shadow copying is done only once per day at max. frequency (disappointing for someone who need every version within a single day). What I am concerned about is my syncTrash folder is growing exponentially - can there be some smart algorithm that doesn't simply just lump all of the previous versions altogether, but rather distinguish the INCREMENTAL changes? This can save tons of space. Not sure if Windows' native shadow copy uses this technology but that will really be fantastic. Also, since the box of "put deleted file into synctrash" is checked by default, user should be somehow made more aware that the trash are hidden and THEY ARE ACTUALLY SITTING THERE AND CONSUMING SPACE - otherwise they may be wondering why the folder is building itself into a ridiculous space-hog. The incremental-smart algorithm will also come handy when it comes to up/download. Say I copy a file in one folder and the app actually upload the copy and redistribute it to peers - but is it really needed? Can it just look around and say - hey let's compare this file to the neighbor. And then it just order other peer to simply copy it as well. This will cost minimal bandwith, but at the cost of more CPU - which I would rather trade in. Also, the tick/wheel icon attached to file icon universal to dropbox/skydrive/etc indicating if the file is in sync or synced is missing here. That's a must. Progress bar is also helpful, as many suggest, especially for large files this will reassure user how soon it can be finished. At last, the current version still have renaming problems - hope this basic functional issue can be resolved. If user cannot even depend on the most basic function, then how can they count on the fancier stuffs?