Great basic functionality but needs some improvements

The actual sync function of the app works very well. It preserves timestamps and gives options for what to do with deleted files. Another nice feature is that it does not litter the directories with temporary or hidden files which some other programs do.
There are however, a few problems. When a sync is running the UI basically freezes because it is working so hard performing the sync. It is nearly impossible to stop or cancel a sync part way through because the UI will not respond. The ability to scan the directories and perform a sync every few seconds or minutes is a nice feature but it would be much better for me and my 100GB photo library that I am syncing to only do it once per day or week at a set time on a schedule. Lastly, the file and directory filters are a great idea but they do not work very well. They do not handle files or directories with spaces in the names. I tried different types of quotes like you would use in terminal scripting but could not get it to work. A visual directory tree with checkboxes to select the included and excluded directories would be perfect (Like windows SyncToy) but just proper parsing of the manually entered text would be acceptable.
All in all this is a good basic sync program with lots of potential but I would not be willing to upgrade to the PRO version (even with the multi directory support) unless some of these issues were dealt with.

SockMacMonkey about Sync Folders, v2.7.1