Syncplicity vs Dropbox
Dropbox is a great service that I still use alongside Syncplicity, but it is very different. DB gives you a single directory to work with, forcing you to move files and folders to the DB parent in order to mirror them. This is great for some things but Syncplicity works everywhere, on any folder, on any drive. In other words, you don't have to change anything in terms of how you organize your files - just map a folder and you're done.
There are also a bunch of other benefits beyond DB - open API as mentioned above for one. Another big difference for me is that Syncplicity allowed me to to delete my iDrive account. There are tons of files I want to store remotely without having any local copy. With DB that isn't an option. With Syncplicity you can map a directory and once it's done syncing you can unmap it and delete it. Then you can hand pick files at any time from the Web UI or simply remap it on any computer and pull the whole thing down again.
Dropbox has Delta Sync capabilities. Alan says:
You're forgetting one of the most important aspects of delta sync, and the one thing that makes Dropbox so efficient: it compares the blocks of packets that it sees it needs to upload to everything on its servers.
Here's an example, because this is a little complicated. I had a 750-MB video file that I wanted to share with my mother who was across the country. It was an HD-video file (H.264, obviously), so yes, it was largely compressed on its own. The file was a common documentary file. After downloading it, I renamed it to fit my computer's organization scheme. When I told Dropbox to upload it, I noticed that the network usage monitor on my Mac's Dashboard only reported about 70 MB uploaded. I checked on Dropbox's website, and yes, my complete file was there, although it had only uploaded 1/10 of its data.
It turns out that what makes Dropbox so efficient is that it looks for similarities in its blocks of packets in other users' uploaded things. So this means that someone else using Dropbox has uploaded this particular HD video, even if it had a different filename and file metadata, but because the underlying video was the same, it only had to upload around 70 MB out of a 750-MB file.
I'm not trying to say that you're wrong, but saying that Dropbox isn't anywhere near as efficient as they claim to be is misleading. Sure, in those situations you're describing, you might be right. However, they have taken many, many steps to streamline the process. However, I am still a dedicated Syncplicity user and will leave Dropbox forever if/when the Mac client is re-released.