OK tried the free version of Foldersync. No Tasker integration but gives me an idea of what can be done.
Tried 2 types of syncs to transfer stuff from my phone onto Dropbox-
(1) Device to Cloud direct over wifi
The simplest most direct method is to create a "folderpair" between a device folder and a DB folder and let them sync over wifi. This uploads the content directly to the cloud. Of course the 1st sync took a long long time as there were 300+ files to sync. I theorized that my device internet upload connection was slow so thot i try (2) below..
(2) Device to Dropbox folder on my xp pc using windows sharing on wifi.
Theoratically, transferring files to your pc over wifi (using windows sharing) should be way faster then uploading to the cloud thru your internet connection right? That was the idea behind this method as i wanted the files over to the desktop Dropbox folder on my pc quickly then let the desktop DB folder sync to the cloud using my always-on pc's internet connection at its own pace (saving battery and wifi connection time on my device).
But actual tests showed that the wifi transferring of files between device and windows using Foldersync was actually similar or slower then uploading to cloud direct. Tried it with Syncme Wireless and that seemed to be much faster at Windows file sharing transfer compared to Foldersync.
I also tried 2 other free apps for DB that have tasker integration/plugin - Dropspace and Dropsync. Dropspace is only 1-way (device to cloud) and is good if u can live with this restriction. Dropsync (free) is 2-way but has got other limitations such as 5-mb file size limit so its useless. And the paid version costs about double that of Foldersync (which has a lot more services).
So, here's the conclusion. If u want to sync between device and DB directly, Foldersync is good, although u'll have to get the paid version for tasker integration. If u transfer a large amount of files between your pc and device, then Foldersync is slow but at least it works with Tasker. (or u can manually sync using Syncme Wireless if u can live without the tasker integration)