Why did you say real time sync is VERY effective? Is it an advertisement only?
No, it's not. The reason is simple and easy to understand: Beyond Sync real time file sync doesn't scan folders for detecting changes. You might didn't notice the performance issue when your folders contain only hundreds of files. That's because the folder scanning is pretty fast. However, if you have more files, e.g. 100 thousands, or you are synchronizing network folders, you'll notice that the folder scanning takes some time. Furthermore, in most time, there are only several files changed.
By using real time file sync, Beyond Sync doesn't scan the folder at all. So, no matter how many files you have, it always has the same and the best performance. Watch Beyond Sync real time sync demo.