I do use full-disk encryption for my local disk as a whole, but for things inside syncing services like Dropbox, block-level encryption kills a number of the useful features and ends up wasting way more transfer to sync changes.
I know they could potentially do cute de-duping tricks on their end, similar to tarsnap, but even if they passed those space savings on to me I'd still lose the file-level features.
That's why I chose EncFS to begin with, and asked for potential other file-level tools to replace it. Realistically, I'd prefer if this expedited EncFS 2.0 and 2.0 fixed the noted issues.
You could use a revision control filesystem like Git on top of the block encryption of dm-crypt [in a loopback]. Git takes care of de-duplication and compression for you, so the blocks you transfer are just changed ones. Of course, this also means your Dropbox will never shrink, so I hope you really like keeping old copies of files ;)
