What are the differences? I'm using 1.x and haven't found it lacking yet. I tried 2.x for a work password db and didn't find anything that really stuck out from my casual usage of it.

One difference I immediately see is 2.x doesn't use lock files. If you sync password DB's using Dropbox, all you need to do is relaunch the software to open the updated DB.

I use 1.x mostly as a backup.

Multiple file attachments in entries. I think 1.x only supports one attachment per entry.